diff --git a/.circleci/config.yml b/.circleci/config.yml
index 1a3393c275..63c2ea4a0e 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -43,7 +43,7 @@ jobs:
     - run: |
         dockerize -wait tcp://localhost:8080 -- \
           muffet \
-            -e 'https://github\.com/runatlantis/atlantis/edit/master/.*' \
+            -e 'https://github\.com/runatlantis/atlantis/edit/main/.*' \
             -e 'https://github.com/runatlantis/helm-charts#customization' \
             --header 'Accept-Encoding:deflate, gzip' \
             --buffer-size 8192 \
diff --git a/.github/ISSUE_TEMPLATE/feature_request.md b/.github/ISSUE_TEMPLATE/feature_request.md
index 647f07ffc7..6e661b9768 100644
--- a/.github/ISSUE_TEMPLATE/feature_request.md
+++ b/.github/ISSUE_TEMPLATE/feature_request.md
@@ -19,7 +19,7 @@ assignees: ''
 
 ---
 
-- [ ] I'd be willing to implement this feature ([contributing guide](https://github.com/runatlantis/atlantis/blob/master/CONTRIBUTING.md))
+- [ ] I'd be willing to implement this feature ([contributing guide](https://github.com/runatlantis/atlantis/blob/main/CONTRIBUTING.md))
 
 **Describe the user story**
 <!--
diff --git a/.github/workflows/atlantis-base.yml b/.github/workflows/atlantis-base.yml
index d275387fc4..f5f1280bc1 100644
--- a/.github/workflows/atlantis-base.yml
+++ b/.github/workflows/atlantis-base.yml
@@ -6,7 +6,7 @@ on:
       - 'docker-base/**'
       - '.github/workflows/atlantis-base.yml'
     branches:
-      - "master"
+      - "main"
   pull_request:
     paths:
       - 'docker-base/**'
diff --git a/.github/workflows/atlantis-image.yml b/.github/workflows/atlantis-image.yml
index 75b0fcd8da..e9389e3da4 100644
--- a/.github/workflows/atlantis-image.yml
+++ b/.github/workflows/atlantis-image.yml
@@ -3,7 +3,7 @@ name: atlantis-image
 on:
   push:
     branches:
-      - 'master'
+      - 'main'
     tags:
       - v*.*.* # stable release like, v0.19.2
       - v*.*.*-pre.* # pre release like, v0.19.0-pre.calendardate
diff --git a/.github/workflows/ci-link-checker-image.yml b/.github/workflows/ci-link-checker-image.yml
index 81fff31f85..8b8efab170 100644
--- a/.github/workflows/ci-link-checker-image.yml
+++ b/.github/workflows/ci-link-checker-image.yml
@@ -5,7 +5,7 @@ on:
     paths:
       - '.github/website_link_checker/**'
     branches:
-      - "master"
+      - "main"
   workflow_dispatch:
 
 concurrency:
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b91cf387d5..0838078513 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -35,7 +35,7 @@ jobs:
         echo "::set-output name=RELEASE_TAG::${GITHUB_REF#refs/tags/}"
         gh api repos/$GITHUB_REPOSITORY/releases/generate-notes \
           -f tag_name="${GITHUB_REF#refs/tags/}" \
-          -f target_commitish=master \
+          -f target_commitish=main \
           -q .body > tmp-CHANGELOG.md
       env:
         GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 5041a8b635..1e45370b1f 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -3,10 +3,10 @@ name: tester
 on:
   push:
     branches:
-      - "master"
+      - "main"
   pull_request:
     branches:
-      - "master"
+      - "main"
 concurrency:
   group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
   cancel-in-progress: true
diff --git a/.github/workflows/testing-env-image.yml b/.github/workflows/testing-env-image.yml
index ef970f1b01..f67e74b2ce 100644
--- a/.github/workflows/testing-env-image.yml
+++ b/.github/workflows/testing-env-image.yml
@@ -6,7 +6,7 @@ on:
       - "testing/**"
       - ".github/workflows/testing-env-image.yml"
     branches:
-      - "master"
+      - "main"
   pull_request:
     paths:
       - 'testing/**'
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1802cb1dac..e70b3756ee 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1723,7 +1723,7 @@ These are the changes in detail:
     ```
 
     The `w` group permission was added so that in OpenShift, the random uid can write
-    their own login entry (https://github.com/runatlantis/atlantis/blob/master/docker-entrypoint.sh#L28)
+    their own login entry (https://github.com/runatlantis/atlantis/blob/main/docker-entrypoint.sh#L28)
     which is required because `terraform` expects the running user to have an entry
     in `/etc/passwd`.
 
@@ -2466,7 +2466,7 @@ None
 assume role session with the GitHub username of the user running the Atlantis command
 use the `atlantis_user` terraform variable alongside Terraform's
 [built-in support](https://www.terraform.io/docs/providers/aws/#assume-role) for assume role
-(see https://github.com/runatlantis/atlantis/blob/master/README.md#assume-role-session-names)
+(see https://github.com/runatlantis/atlantis/blob/main/README.md#assume-role-session-names)
 * Atlantis has a docker image now ([#123](https://github.com/hootsuite/atlantis/pull/123)). Here is how you can try it out:
 
 ```bash
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 864293f65c..f5863a9126 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -16,7 +16,7 @@ We take security issues seriously. Please email us directly at security [at] run
 # Updating The Website
 * To view the generated website locally, run `yarn website:dev` and then
 open your browser to http://localhost:8080.
-* The website will be regenerated when your pull request is merged to master.
+* The website will be regenerated when your pull request is merged to main.
 
 # Developing
 
@@ -78,7 +78,7 @@ docker run --rm -v $(pwd):/go/src/github.com/runatlantis/atlantis -w /go/src/git
 
 ## Calling Your Local Atlantis From GitHub
 - Create a test terraform repository in your GitHub.
-- Create a personal access token for Atlantis. See [Create a GitHub token](https://github.com/runatlantis/atlantis/tree/master/runatlantis.io/docs/access-credentials.md#generating-an-access-token).
+- Create a personal access token for Atlantis. See [Create a GitHub token](https://github.com/runatlantis/atlantis/tree/main/runatlantis.io/docs/access-credentials.md#generating-an-access-token).
 - Start Atlantis in server mode using that token:
 ```
 atlantis server --gh-user <your username> --gh-token <your token> --repo-allowlist <your repo> --gh-webhook-secret <your webhook secret> --log-level debug
@@ -88,7 +88,7 @@ atlantis server --gh-user <your username> --gh-token <your token> --repo-allowli
 ```
 ngrok http 4141
 ```
-- Create a Webhook in your repo and use the `https` url that `ngrok` printed out after running `ngrok http 4141`. Be sure to append `/events` so your webhook url looks something like `https://efce3bcd.ngrok.io/events`. See [Add GitHub Webhook](https://github.com/runatlantis/atlantis/blob/master/runatlantis.io/docs/configuring-webhooks.md#configuring-webhooks).
+- Create a Webhook in your repo and use the `https` url that `ngrok` printed out after running `ngrok http 4141`. Be sure to append `/events` so your webhook url looks something like `https://efce3bcd.ngrok.io/events`. See [Add GitHub Webhook](https://github.com/runatlantis/atlantis/blob/main/runatlantis.io/docs/configuring-webhooks.md#configuring-webhooks).
 - Create a pull request and type `atlantis help`. You should see the request in the `ngrok` and Atlantis logs and you should also see Atlantis comment back.
 
 ## Code Style
@@ -163,9 +163,9 @@ go get github.com/petergtz/pegomock/...
 # Creating a New Release
 1. Update version number in `main.go`.
 1. Update image tag version in the [kustomize/bundle.yaml](kustomize/bundle.yaml).
-1. Update `CHANGELOG.md` with latest release number and information (this URL might be useful: https://github.com/runatlantis/atlantis/compare/v0.3.5...master)
-1. Create a pull request and merge to master
-1. Check out master and fetch latest
+1. Update `CHANGELOG.md` with latest release number and information (this URL might be useful: https://github.com/runatlantis/atlantis/compare/v0.3.5...main)
+1. Create a pull request and merge to main
+1. Check out main and fetch latest
 1. Run `make release`
     1. If you get `signal: killed` errors, bump up your Docker resources to have more memory, e.g. 6 G.B.
 1. Go to https://github.com/runatlantis/atlantis/releases and click "Draft a new release"
@@ -173,5 +173,5 @@ go get github.com/petergtz/pegomock/...
     1. The title of the release is the same as the tag (ex. v0.2.2)
     1. Fill in description by copying from the CHANGELOG just without the Downloads section
     1. Drag in binaries made with `make release`
-1. Re-run master branch build to ensure tag gets pushed to Github: https://github.com/runatlantis/atlantis/pkgs/container/atlantis
+1. Re-run main branch build to ensure tag gets pushed to Github: https://github.com/runatlantis/atlantis/pkgs/container/atlantis
 1. Update the default version in `Chart.yaml` in [the official Helm chart](https://github.com/runatlantis/helm-charts/blob/main/charts/atlantis/values.yaml).
diff --git a/README.md b/README.md
index f0b7dd2434..52be8e15af 100644
--- a/README.md
+++ b/README.md
@@ -2,8 +2,8 @@
 
 [![SuperDopeBadge](./runatlantis.io/.vuepress/public/hightower-super-dope.svg)](https://twitter.com/kelseyhightower/status/893260922222813184)
 [![Go Report Card](https://goreportcard.com/badge/github.com/runatlantis/atlantis)](https://goreportcard.com/report/github.com/runatlantis/atlantis)
-[![codecov](https://codecov.io/gh/runatlantis/atlantis/branch/master/graph/badge.svg)](https://codecov.io/gh/runatlantis/atlantis)
-[![CircleCI](https://circleci.com/gh/runatlantis/atlantis/tree/master.svg?style=shield)](https://circleci.com/gh/runatlantis/atlantis/tree/master)
+[![codecov](https://codecov.io/gh/runatlantis/atlantis/branch/main/graph/badge.svg)](https://codecov.io/gh/runatlantis/atlantis)
+[![CircleCI](https://circleci.com/gh/runatlantis/atlantis/tree/main.svg?style=shield)](https://circleci.com/gh/runatlantis/atlantis/tree/main)
 [![Slack](https://img.shields.io/badge/Join-Atlantis%20Community%20Slack-red)](https://join.slack.com/t/atlantis-community/shared_invite/enQtNzc4NDM3OTA3ODI0LTA5NDQ4YTA3NTAxM2I3ZmIxMGNiYWJhNmY4YjBjZjM3OWMzNGI0NTcxNzY2NjRhODIyODA4YmNjOTBiOThhNTI)
 
 <p align="center">
diff --git a/cmd/server.go b/cmd/server.go
index 96eda6d5ac..016830603b 100644
--- a/cmd/server.go
+++ b/cmd/server.go
@@ -204,7 +204,7 @@ var stringFlags = map[string]stringFlag{
 	CheckoutStrategyFlag: {
 		description: "How to check out pull requests. Accepts either 'branch' (default) or 'merge'." +
 			" If set to branch, Atlantis will check out the source branch of the pull request." +
-			" If set to merge, Atlantis will check out the destination branch of the pull request (ex. master)" +
+			" If set to merge, Atlantis will check out the destination branch of the pull request (ex. main, master)" +
 			" and then locally perform a git merge of the source branch." +
 			" This effectively means Atlantis operates on the repo as it will look" +
 			" after the pull request is merged.",
diff --git a/e2e/e2e.go b/e2e/e2e.go
index 5addf721e0..68aef4ce5d 100644
--- a/e2e/e2e.go
+++ b/e2e/e2e.go
@@ -110,7 +110,7 @@ func (t *E2ETester) Start() (*E2EResult, error) {
 	title := fmt.Sprintf("This is a test pull request for atlantis e2e test for %s project type", t.projectType.Name)
 	head := fmt.Sprintf("%s:%s", t.ownerName, branchName)
 	body := ""
-	base := "master"
+	base := "main"
 	newPullRequest := &github.NewPullRequest{Title: &title, Head: &head, Body: &body, Base: &base}
 
 	pull, _, err := t.githubClient.client.PullRequests.Create(t.githubClient.ctx, t.ownerName, t.repoName, newPullRequest)
diff --git a/runatlantis.io/.vuepress/components/HomeCustom.vue b/runatlantis.io/.vuepress/components/HomeCustom.vue
index 27fe34e979..b4691cd0db 100644
--- a/runatlantis.io/.vuepress/components/HomeCustom.vue
+++ b/runatlantis.io/.vuepress/components/HomeCustom.vue
@@ -35,7 +35,7 @@
                   the Terraform plan output before it's applied.
                 </li>
                 <li><img class="checkmark" src="/checkmark.svg">Ensure that you
-                  apply changes before merging to master.
+                  apply changes before merging to main.
                 </li>
               </ul>
             </div>
diff --git a/runatlantis.io/docs/apply-requirements.md b/runatlantis.io/docs/apply-requirements.md
index d4dcddaf6b..4fa7edf3d7 100644
--- a/runatlantis.io/docs/apply-requirements.md
+++ b/runatlantis.io/docs/apply-requirements.md
@@ -103,7 +103,7 @@ If you set up Protected Branches then you can enforce:
 * Requiring certain status checks to be passing
 * Requiring certain people to have reviewed and approved the pull request
 * Requiring `CODEOWNERS` to have reviewed and approved the pull request
-* Requiring that the branch is up to date with `master`
+* Requiring that the branch is up to date with `main`
 
 See [https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/defining-the-mergeability-of-pull-requests/about-protected-branches](https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/defining-the-mergeability-of-pull-requests/about-protected-branches)
 for more details.
@@ -176,7 +176,7 @@ You can set the `undiverged` requirement by:
 #### Meaning
 The `merge` checkout strategy creates a temporary merge commit and runs the `plan` on the Atlantis local version of the PR
 source and destination branch. The local destination branch can become out of date since changes to the destination branch are not fetched
-if there are no changes to the source branch. `undiverged` enforces that Atlantis local version of master is up to date
+if there are no changes to the source branch. `undiverged` enforces that Atlantis local version of main is up to date
 with remote so that the state of the source during the `apply` is identical to that if you were to merge the PR at that
 time.
 
diff --git a/runatlantis.io/docs/checkout-strategy.md b/runatlantis.io/docs/checkout-strategy.md
index 01ffdbedc4..d58c875235 100644
--- a/runatlantis.io/docs/checkout-strategy.md
+++ b/runatlantis.io/docs/checkout-strategy.md
@@ -13,24 +13,24 @@ of the pull request.
 For example, given the following git history:
 ![Git History](./images/branch-strategy.png)
 
-If the pull request was asking to merge `branch` into `master`,
+If the pull request was asking to merge `branch` into `main`,
 Atlantis would check out `branch` at commit `C3`.
 
 ## Merge
 The problem with the `branch` strategy, is that if users push branches that are
-out of date with `master`, then their `terraform plan` could be deleting
-some resources that were configured in the master branch.
+out of date with `main`, then their `terraform plan` could be deleting
+some resources that were configured in the main branch.
 
 For example, in the above diagram if commits `C4` and `C5` have modified the
 terraform state and added new resources, then when Atlantis runs `terraform plan`
 at commit `C3`, because the code doesn't have the changes from `C4` and `C5`,
 Terraform will try to delete those resources.
 
-To fix this, users could merge `master` into their branch, *or* you can run
+To fix this, users could merge `main` into their branch, *or* you can run
 Atlantis with `--checkout-strategy=merge`. With this strategy, Atlantis will
 try to perform a merge locally by:
 
-* Checking out the destination branch of the pull request (ex. `master`)
+* Checking out the destination branch of the pull request (ex. `main`)
 * Locally performing a `git merge {source branch}`
 * Then running its Terraform commands
 
@@ -44,5 +44,5 @@ Atlantis doesn't actually commit this merge anywhere. It just uses it locally.
 
 :::warning
 Atlantis only performs this merge during the `terraform plan` phase. If another
-commit is pushed to `master` **after** Atlantis runs `plan`, nothing will happen.
+commit is pushed to `main` **after** Atlantis runs `plan`, nothing will happen.
 :::
diff --git a/runatlantis.io/docs/locking.md b/runatlantis.io/docs/locking.md
index f3e32b8745..526d4f644a 100644
--- a/runatlantis.io/docs/locking.md
+++ b/runatlantis.io/docs/locking.md
@@ -16,14 +16,14 @@ Only the directory in the repo and Terraform workspace are locked, not the whole
 
 ## Why
 1. Because `atlantis apply` is being done before the pull request is merged, after
-an apply your `master` branch does not represent the most up to date version of your infrastructure
+an apply your `main` branch does not represent the most up to date version of your infrastructure
 anymore. With locking, you can ensure that no other changes will be made until the
 pull request is merged.
 
 ::: tip Why not apply on merge?
 Sometimes `terraform apply` fails. If the apply were to fail after the pull
 request was merged, you would need to create a new pull request to fix it.
-With locking + applying on the branch, you effectively mimic merging to master
+With locking + applying on the branch, you effectively mimic merging to main
 but with the added ability to re-plan/apply multiple times if things don't work.
 :::
 2. If there is already a `plan` in progress, other users won't see a plan that
diff --git a/runatlantis.io/docs/security.md b/runatlantis.io/docs/security.md
index bed3b92495..489e313a9b 100644
--- a/runatlantis.io/docs/security.md
+++ b/runatlantis.io/docs/security.md
@@ -15,7 +15,7 @@ Atlantis could be exploited by
       }
     }
     ```
-* Running malicious custom build commands specified in an `atlantis.yaml` file. Atlantis uses the `atlantis.yaml` file from the pull request branch, **not** `master`.
+* Running malicious custom build commands specified in an `atlantis.yaml` file. Atlantis uses the `atlantis.yaml` file from the pull request branch, **not** `main`.
 * Someone adding `atlantis plan/apply` comments on your valid pull requests causing terraform to run when you don't want it to.
 
 ## Bitbucket Cloud (bitbucket.org)
diff --git a/runatlantis.io/guide/README.md b/runatlantis.io/guide/README.md
index a8e36beded..15472518b8 100644
--- a/runatlantis.io/guide/README.md
+++ b/runatlantis.io/guide/README.md
@@ -29,7 +29,7 @@ Check out the video below to see it in action:
 ### Increased visibility
 When everyone is executing Terraform on their own computers, it's hard to know the
 current state of your infrastructure:
-* Is what's in `master` deployed?
+* Is what's in `main` branch deployed?
 * Did someone forget to create a pull request for that latest change?
 * What was the output from that last `terraform apply`?
 
diff --git a/server/controllers/events/events_controller_e2e_test.go b/server/controllers/events/events_controller_e2e_test.go
index 88252827e5..70d444ccee 100644
--- a/server/controllers/events/events_controller_e2e_test.go
+++ b/server/controllers/events/events_controller_e2e_test.go
@@ -1234,7 +1234,7 @@ func GitHubPullRequestParsed(headSHA string) *github.PullRequest {
 				FullName: github.String("runatlantis/atlantis-tests"),
 				CloneURL: github.String("https://github.com/runatlantis/atlantis-tests.git"),
 			},
-			Ref: github.String("master"),
+			Ref: github.String("main"),
 		},
 		User: &github.User{
 			Login: github.String("atlantisbot"),
diff --git a/server/controllers/events/events_controller_test.go b/server/controllers/events/events_controller_test.go
index 92da51fe1c..84c5a32875 100644
--- a/server/controllers/events/events_controller_test.go
+++ b/server/controllers/events/events_controller_test.go
@@ -697,7 +697,7 @@ func TestPost_BBServerPullClosed(t *testing.T) {
 				HeadCommit: "2d9fb6b9a46eafb1dcef7b008d1a429d45ca742c",
 				URL:        "https://bbserver.com/projects/PROJ/repos/repository/pull-requests/10",
 				HeadBranch: "decline-me",
-				BaseBranch: "master",
+				BaseBranch: "main",
 				Author:     "admin",
 				State:      models.OpenPullState,
 				BaseRepo:   expRepo,
diff --git a/server/controllers/events/gitlab_request_parser_validator_test.go b/server/controllers/events/gitlab_request_parser_validator_test.go
index ae1269998c..ea3c43acd5 100644
--- a/server/controllers/events/gitlab_request_parser_validator_test.go
+++ b/server/controllers/events/gitlab_request_parser_validator_test.go
@@ -157,7 +157,7 @@ var mergeEventJSON = `{
     "namespace": "lkysow",
     "visibility_level": 20,
     "path_with_namespace": "lkysow/atlantis-example",
-    "default_branch": "master",
+    "default_branch": "main",
     "ci_config_path": null,
     "homepage": "https://gitlab.com/lkysow/atlantis-example",
     "url": "git@gitlab.com:lkysow/atlantis-example.git",
@@ -186,7 +186,7 @@ var mergeEventJSON = `{
     "source_branch": "patch-1",
     "source_project_id": 4580910,
     "state": "opened",
-    "target_branch": "master",
+    "target_branch": "main",
     "target_project_id": 4580910,
     "time_estimate": 0,
     "title": "Update main.tf",
@@ -204,7 +204,7 @@ var mergeEventJSON = `{
       "namespace": "sourceorg",
       "visibility_level": 20,
       "path_with_namespace": "sourceorg/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/sourceorg/atlantis-example",
       "url": "git@gitlab.com:sourceorg/atlantis-example.git",
@@ -222,7 +222,7 @@ var mergeEventJSON = `{
       "namespace": "lkysow",
       "visibility_level": 20,
       "path_with_namespace": "lkysow/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/lkysow/atlantis-example",
       "url": "git@gitlab.com:lkysow/atlantis-example.git",
@@ -286,7 +286,7 @@ var mergeEventJSON = `{
     },
     "target_branch": {
       "previous": null,
-      "current": "master"
+      "current": "main"
     },
     "target_project_id": {
       "previous": null,
@@ -333,7 +333,7 @@ var mergeCommentEventJSON = `{
     "namespace":"Gitlab Org",
     "visibility_level":10,
     "path_with_namespace":"gitlabhq/gitlab-test",
-    "default_branch":"master",
+    "default_branch":"main",
     "homepage":"http://example.com/gitlabhq/gitlab-test",
     "url":"https://example.com/gitlabhq/gitlab-test.git",
     "ssh_url":"git@example.com:gitlabhq/gitlab-test.git",
@@ -364,7 +364,7 @@ var mergeCommentEventJSON = `{
   "merge_request": {
     "id": 7,
     "target_branch": "markdown",
-    "source_branch": "master",
+    "source_branch": "main",
     "source_project_id": 5,
     "author_id": 8,
     "assignee_id": 28,
@@ -388,7 +388,7 @@ var mergeCommentEventJSON = `{
       "namespace":"Gitlab Org",
       "visibility_level":10,
       "path_with_namespace":"gitlab-org/gitlab-test",
-      "default_branch":"master",
+      "default_branch":"main",
       "homepage":"http://example.com/gitlab-org/gitlab-test",
       "url":"https://example.com/gitlab-org/gitlab-test.git",
       "ssh_url":"git@example.com:gitlab-org/gitlab-test.git",
@@ -405,7 +405,7 @@ var mergeCommentEventJSON = `{
       "namespace":"Gitlab Org",
       "visibility_level":10,
       "path_with_namespace":"gitlabhq/gitlab-test",
-      "default_branch":"master",
+      "default_branch":"main",
       "homepage":"http://example.com/gitlabhq/gitlab-test",
       "url":"https://example.com/gitlabhq/gitlab-test.git",
       "ssh_url":"git@example.com:gitlabhq/gitlab-test.git",
@@ -413,7 +413,7 @@ var mergeCommentEventJSON = `{
     },
     "last_commit": {
       "id": "562e173be03b8ff2efb05345d12df18815438a4b",
-      "message": "Merge branch 'another-branch' into 'master'\n\nCheck in this test\n",
+      "message": "Merge branch 'another-branch' into 'main'\n\nCheck in this test\n",
       "timestamp": "2002-10-02T10:00:00-05:00",
       "url": "http://example.com/gitlab-org/gitlab-test/commit/562e173be03b8ff2efb05345d12df18815438a4b",
       "author": {
@@ -449,7 +449,7 @@ var commitCommentEventJSON = `{
     "namespace":"GitlabHQ",
     "visibility_level":20,
     "path_with_namespace":"gitlabhq/gitlab-test",
-    "default_branch":"master",
+    "default_branch":"main",
     "homepage":"http://example.com/gitlabhq/gitlab-test",
     "url":"http://example.com/gitlabhq/gitlab-test.git",
     "ssh_url":"git@example.com:gitlabhq/gitlab-test.git",
diff --git a/server/controllers/events/testfixtures/bb-server-pull-deleted-event.json b/server/controllers/events/testfixtures/bb-server-pull-deleted-event.json
index 29f83137b1..d8a3507c31 100644
--- a/server/controllers/events/testfixtures/bb-server-pull-deleted-event.json
+++ b/server/controllers/events/testfixtures/bb-server-pull-deleted-event.json
@@ -42,8 +42,8 @@
       }
     },
     "toRef":{
-      "id":"refs/heads/master",
-      "displayId":"master",
+      "id":"refs/heads/main",
+      "displayId":"main",
       "latestCommit":"7e48f426f0a6e47c5b5e862c31be6ca965f82c9c",
       "repository":{
         "slug":"repository",
diff --git a/server/controllers/events/testfixtures/githubIssueCommentEvent.json b/server/controllers/events/testfixtures/githubIssueCommentEvent.json
index a15f67ed4a..6f85548207 100644
--- a/server/controllers/events/testfixtures/githubIssueCommentEvent.json
+++ b/server/controllers/events/testfixtures/githubIssueCommentEvent.json
@@ -182,7 +182,7 @@
     "forks": 0,
     "open_issues": 2,
     "watchers": 0,
-    "default_branch": "master"
+    "default_branch": "main"
   },
   "sender": {
     "login": "runatlantis",
@@ -204,4 +204,4 @@
     "type": "User",
     "site_admin": false
   }
-}
\ No newline at end of file
+}
diff --git a/server/controllers/events/testfixtures/githubIssueCommentEvent_notAllowlisted.json b/server/controllers/events/testfixtures/githubIssueCommentEvent_notAllowlisted.json
index 0a71381c49..0e61cf6fdc 100644
--- a/server/controllers/events/testfixtures/githubIssueCommentEvent_notAllowlisted.json
+++ b/server/controllers/events/testfixtures/githubIssueCommentEvent_notAllowlisted.json
@@ -158,7 +158,7 @@
     "forks": 0,
     "open_issues": 2,
     "watchers": 0,
-    "default_branch": "master"
+    "default_branch": "main"
   },
   "sender": {
     "login": "baxterthehacker",
@@ -179,4 +179,4 @@
     "type": "User",
     "site_admin": false
   }
-}
\ No newline at end of file
+}
diff --git a/server/controllers/events/testfixtures/githubPullRequestClosedEvent.json b/server/controllers/events/testfixtures/githubPullRequestClosedEvent.json
index cc281a8d7a..2cb9a014b6 100644
--- a/server/controllers/events/testfixtures/githubPullRequestClosedEvent.json
+++ b/server/controllers/events/testfixtures/githubPullRequestClosedEvent.json
@@ -179,12 +179,12 @@
         "forks": 0,
         "open_issues": 1,
         "watchers": 0,
-        "default_branch": "master"
+        "default_branch": "main"
       }
     },
     "base": {
-      "label": "runatlantis:master",
-      "ref": "master",
+      "label": "runatlantis:main",
+      "ref": "main",
       "sha": "f59a822e83b3cd193142c7624ea635a5d7894388",
       "user": {
         "login": "runatlantis",
@@ -303,7 +303,7 @@
         "forks": 0,
         "open_issues": 1,
         "watchers": 0,
-        "default_branch": "master"
+        "default_branch": "main"
       }
     },
     "_links": {
@@ -443,7 +443,7 @@
     "forks": 0,
     "open_issues": 1,
     "watchers": 0,
-    "default_branch": "master"
+    "default_branch": "main"
   },
   "sender": {
     "login": "runatlantis",
@@ -465,4 +465,4 @@
     "type": "User",
     "site_admin": false
   }
-}
\ No newline at end of file
+}
diff --git a/server/controllers/events/testfixtures/githubPullRequestOpenedEvent.json b/server/controllers/events/testfixtures/githubPullRequestOpenedEvent.json
index 03ee106b5e..a2ea2c7d21 100644
--- a/server/controllers/events/testfixtures/githubPullRequestOpenedEvent.json
+++ b/server/controllers/events/testfixtures/githubPullRequestOpenedEvent.json
@@ -179,12 +179,12 @@
         "forks": 0,
         "open_issues": 2,
         "watchers": 0,
-        "default_branch": "master"
+        "default_branch": "main"
       }
     },
     "base": {
-      "label": "runatlantis:master",
-      "ref": "master",
+      "label": "runatlantis:main",
+      "ref": "main",
       "sha": "f59a822e83b3cd193142c7624ea635a5d7894388",
       "user": {
         "login": "runatlantis",
@@ -303,7 +303,7 @@
         "forks": 0,
         "open_issues": 2,
         "watchers": 0,
-        "default_branch": "master"
+        "default_branch": "main"
       }
     },
     "_links": {
@@ -443,7 +443,7 @@
     "forks": 0,
     "open_issues": 2,
     "watchers": 0,
-    "default_branch": "master"
+    "default_branch": "main"
   },
   "sender": {
     "login": "runatlantis",
@@ -465,4 +465,4 @@
     "type": "User",
     "site_admin": false
   }
-}
\ No newline at end of file
+}
diff --git a/server/controllers/events/testfixtures/gitlabMergeCommentEvent_notAllowlisted.json b/server/controllers/events/testfixtures/gitlabMergeCommentEvent_notAllowlisted.json
index aa364d214f..98312f9930 100644
--- a/server/controllers/events/testfixtures/gitlabMergeCommentEvent_notAllowlisted.json
+++ b/server/controllers/events/testfixtures/gitlabMergeCommentEvent_notAllowlisted.json
@@ -17,7 +17,7 @@
     "namespace":"Gitlab Org",
     "visibility_level":10,
     "path_with_namespace":"gitlabhq/gitlab-test",
-    "default_branch":"master",
+    "default_branch":"main",
     "homepage":"http://example.com/gitlabhq/gitlab-test",
     "url":"https://example.com/gitlabhq/gitlab-test.git",
     "ssh_url":"git@example.com:gitlabhq/gitlab-test.git",
@@ -48,7 +48,7 @@
   "merge_request": {
     "id": 7,
     "target_branch": "markdown",
-    "source_branch": "master",
+    "source_branch": "main",
     "source_project_id": 5,
     "author_id": 8,
     "assignee_id": 28,
@@ -72,7 +72,7 @@
       "namespace":"Gitlab Org",
       "visibility_level":10,
       "path_with_namespace":"gitlab-org/gitlab-test",
-      "default_branch":"master",
+      "default_branch":"main",
       "homepage":"http://example.com/gitlab-org/gitlab-test",
       "url":"https://example.com/gitlab-org/gitlab-test.git",
       "ssh_url":"git@example.com:gitlab-org/gitlab-test.git",
@@ -89,7 +89,7 @@
       "namespace":"Gitlab Org",
       "visibility_level":10,
       "path_with_namespace":"gitlabhq/gitlab-test",
-      "default_branch":"master",
+      "default_branch":"main",
       "homepage":"http://example.com/gitlabhq/gitlab-test",
       "url":"https://example.com/gitlabhq/gitlab-test.git",
       "ssh_url":"git@example.com:gitlabhq/gitlab-test.git",
@@ -97,7 +97,7 @@
     },
     "last_commit": {
       "id": "562e173be03b8ff2efb05345d12df18815438a4b",
-      "message": "Merge branch 'another-branch' into 'master'\n\nCheck in this test\n",
+      "message": "Merge branch 'another-branch' into 'main'\n\nCheck in this test\n",
       "timestamp": "2002-10-02T10:00:00-05:00",
       "url": "http://example.com/gitlab-org/gitlab-test/commit/562e173be03b8ff2efb05345d12df18815438a4b",
       "author": {
@@ -112,4 +112,4 @@
       "avatar_url": "http://www.gravatar.com/avatar/e64c7d89f26bd1972efa854d13d7dd61?s=40\u0026d=identicon"
     }
   }
-}
\ No newline at end of file
+}
diff --git a/server/controllers/events/testfixtures/gitlabMergeCommentEvent_shouldIgnore.json b/server/controllers/events/testfixtures/gitlabMergeCommentEvent_shouldIgnore.json
index d92bc4d45e..8b7548e544 100644
--- a/server/controllers/events/testfixtures/gitlabMergeCommentEvent_shouldIgnore.json
+++ b/server/controllers/events/testfixtures/gitlabMergeCommentEvent_shouldIgnore.json
@@ -17,7 +17,7 @@
     "namespace":"Gitlab Org",
     "visibility_level":10,
     "path_with_namespace":"gitlabhq/gitlab-test",
-    "default_branch":"master",
+    "default_branch":"main",
     "homepage":"http://example.com/gitlabhq/gitlab-test",
     "url":"https://example.com/gitlabhq/gitlab-test.git",
     "ssh_url":"git@example.com:gitlabhq/gitlab-test.git",
@@ -48,7 +48,7 @@
   "merge_request": {
     "id": 7,
     "target_branch": "markdown",
-    "source_branch": "master",
+    "source_branch": "main",
     "source_project_id": 5,
     "author_id": 8,
     "assignee_id": 28,
@@ -72,7 +72,7 @@
       "namespace":"Gitlab Org",
       "visibility_level":10,
       "path_with_namespace":"gitlab-org/gitlab-test",
-      "default_branch":"master",
+      "default_branch":"main",
       "homepage":"http://example.com/gitlab-org/gitlab-test",
       "url":"https://example.com/gitlab-org/gitlab-test.git",
       "ssh_url":"git@example.com:gitlab-org/gitlab-test.git",
@@ -89,7 +89,7 @@
       "namespace":"Gitlab Org",
       "visibility_level":10,
       "path_with_namespace":"gitlabhq/gitlab-test",
-      "default_branch":"master",
+      "default_branch":"main",
       "homepage":"http://example.com/gitlabhq/gitlab-test",
       "url":"https://example.com/gitlabhq/gitlab-test.git",
       "ssh_url":"git@example.com:gitlabhq/gitlab-test.git",
@@ -97,7 +97,7 @@
     },
     "last_commit": {
       "id": "562e173be03b8ff2efb05345d12df18815438a4b",
-      "message": "Merge branch 'another-branch' into 'master'\n\nCheck in this test\n",
+      "message": "Merge branch 'another-branch' into 'main'\n\nCheck in this test\n",
       "timestamp": "2002-10-02T10:00:00-05:00",
       "url": "http://example.com/gitlab-org/gitlab-test/commit/562e173be03b8ff2efb05345d12df18815438a4b",
       "author": {
@@ -112,4 +112,4 @@
       "avatar_url": "http://www.gravatar.com/avatar/e64c7d89f26bd1972efa854d13d7dd61?s=40\u0026d=identicon"
     }
   }
-}
\ No newline at end of file
+}
diff --git a/server/core/config/valid/global_cfg_test.go b/server/core/config/valid/global_cfg_test.go
index 18b5c0e50b..e9bce44fb6 100644
--- a/server/core/config/valid/global_cfg_test.go
+++ b/server/core/config/valid/global_cfg_test.go
@@ -915,7 +915,7 @@ func TestRepo_BranchMatches(t *testing.T) {
 	Equals(t, false, (valid.Repo{BranchRegex: regexp.MustCompile("^main$")}).BranchMatches("foo-main"))
 	Equals(t, false, (valid.Repo{BranchRegex: regexp.MustCompile("^main$")}).BranchMatches("main-foo"))
 	Equals(t, true, (valid.Repo{BranchRegex: regexp.MustCompile("(main|master)")}).BranchMatches("main"))
-	Equals(t, true, (valid.Repo{BranchRegex: regexp.MustCompile("(main|master)")}).BranchMatches("master"))
+	Equals(t, true, (valid.Repo{BranchRegex: regexp.MustCompile("(main|master)")}).BranchMatches("main"))
 	Equals(t, true, (valid.Repo{BranchRegex: regexp.MustCompile("release")}).BranchMatches("release-stage"))
 	Equals(t, false, (valid.Repo{BranchRegex: regexp.MustCompile("release")}).BranchMatches("main"))
 }
@@ -933,7 +933,7 @@ func TestGlobalCfg_MatchingRepo(t *testing.T) {
 	}
 	repo2 := valid.Repo{
 		ID:                "github.com/owner/repo",
-		BranchRegex:       regexp.MustCompile("^master$"),
+		BranchRegex:       regexp.MustCompile("^main$"),
 		ApplyRequirements: []string{"approved", "mergeable"},
 	}
 
diff --git a/server/core/runtime/env_step_runner_test.go b/server/core/runtime/env_step_runner_test.go
index 7a370144c5..3f1f46fdf0 100644
--- a/server/core/runtime/env_step_runner_test.go
+++ b/server/core/runtime/env_step_runner_test.go
@@ -65,7 +65,7 @@ func TestEnvStepRunner_Run(t *testing.T) {
 				Pull: models.PullRequest{
 					Num:        2,
 					HeadBranch: "add-feat",
-					BaseBranch: "master",
+					BaseBranch: "main",
 					Author:     "acme",
 				},
 				User: models.User{
diff --git a/server/core/runtime/multienv_step_runner_test.go b/server/core/runtime/multienv_step_runner_test.go
index be07d3966c..edb3420b3d 100644
--- a/server/core/runtime/multienv_step_runner_test.go
+++ b/server/core/runtime/multienv_step_runner_test.go
@@ -66,7 +66,7 @@ func TestMultiEnvStepRunner_Run(t *testing.T) {
 				Pull: models.PullRequest{
 					Num:        2,
 					HeadBranch: "add-feat",
-					BaseBranch: "master",
+					BaseBranch: "main",
 					Author:     "acme",
 				},
 				User: models.User{
diff --git a/server/core/runtime/post_workflow_hook_runner_test.go b/server/core/runtime/post_workflow_hook_runner_test.go
index e1cc430d7e..dfa741d6d1 100644
--- a/server/core/runtime/post_workflow_hook_runner_test.go
+++ b/server/core/runtime/post_workflow_hook_runner_test.go
@@ -50,7 +50,7 @@ func TestPostWorkflowHookRunner_Run(t *testing.T) {
 		},
 		{
 			Command: "echo base_repo_name=$BASE_REPO_NAME base_repo_owner=$BASE_REPO_OWNER head_repo_name=$HEAD_REPO_NAME head_repo_owner=$HEAD_REPO_OWNER head_branch_name=$HEAD_BRANCH_NAME head_commit=$HEAD_COMMIT base_branch_name=$BASE_BRANCH_NAME pull_num=$PULL_NUM pull_author=$PULL_AUTHOR",
-			ExpOut:  "base_repo_name=basename base_repo_owner=baseowner head_repo_name=headname head_repo_owner=headowner head_branch_name=add-feat head_commit=12345abcdef base_branch_name=master pull_num=2 pull_author=acme\n",
+			ExpOut:  "base_repo_name=basename base_repo_owner=baseowner head_repo_name=headname head_repo_owner=headowner head_branch_name=add-feat head_commit=12345abcdef base_branch_name=main pull_num=2 pull_author=acme\n",
 		},
 		{
 			Command: "echo user_name=$USER_NAME",
@@ -86,7 +86,7 @@ func TestPostWorkflowHookRunner_Run(t *testing.T) {
 					Num:        2,
 					HeadBranch: "add-feat",
 					HeadCommit: "12345abcdef",
-					BaseBranch: "master",
+					BaseBranch: "main",
 					Author:     "acme",
 				},
 				User: models.User{
diff --git a/server/core/runtime/pre_workflow_hook_runner_test.go b/server/core/runtime/pre_workflow_hook_runner_test.go
index 53ba05bfa7..b98b09059d 100644
--- a/server/core/runtime/pre_workflow_hook_runner_test.go
+++ b/server/core/runtime/pre_workflow_hook_runner_test.go
@@ -50,7 +50,7 @@ func TestPreWorkflowHookRunner_Run(t *testing.T) {
 		},
 		{
 			Command: "echo base_repo_name=$BASE_REPO_NAME base_repo_owner=$BASE_REPO_OWNER head_repo_name=$HEAD_REPO_NAME head_repo_owner=$HEAD_REPO_OWNER head_branch_name=$HEAD_BRANCH_NAME head_commit=$HEAD_COMMIT base_branch_name=$BASE_BRANCH_NAME pull_num=$PULL_NUM pull_author=$PULL_AUTHOR",
-			ExpOut:  "base_repo_name=basename base_repo_owner=baseowner head_repo_name=headname head_repo_owner=headowner head_branch_name=add-feat head_commit=12345abcdef base_branch_name=master pull_num=2 pull_author=acme\n",
+			ExpOut:  "base_repo_name=basename base_repo_owner=baseowner head_repo_name=headname head_repo_owner=headowner head_branch_name=add-feat head_commit=12345abcdef base_branch_name=main pull_num=2 pull_author=acme\n",
 		},
 		{
 			Command: "echo user_name=$USER_NAME",
@@ -86,7 +86,7 @@ func TestPreWorkflowHookRunner_Run(t *testing.T) {
 					Num:        2,
 					HeadBranch: "add-feat",
 					HeadCommit: "12345abcdef",
-					BaseBranch: "master",
+					BaseBranch: "main",
 					Author:     "acme",
 				},
 				User: models.User{
diff --git a/server/core/runtime/run_step_runner_test.go b/server/core/runtime/run_step_runner_test.go
index 69cb746bdd..f553d5fff6 100644
--- a/server/core/runtime/run_step_runner_test.go
+++ b/server/core/runtime/run_step_runner_test.go
@@ -72,7 +72,7 @@ func TestRunStepRunner_Run(t *testing.T) {
 		},
 		{
 			Command: "echo base_repo_name=$BASE_REPO_NAME base_repo_owner=$BASE_REPO_OWNER head_repo_name=$HEAD_REPO_NAME head_repo_owner=$HEAD_REPO_OWNER head_branch_name=$HEAD_BRANCH_NAME head_commit=$HEAD_COMMIT base_branch_name=$BASE_BRANCH_NAME pull_num=$PULL_NUM pull_author=$PULL_AUTHOR repo_rel_dir=$REPO_REL_DIR",
-			ExpOut:  "base_repo_name=basename base_repo_owner=baseowner head_repo_name=headname head_repo_owner=headowner head_branch_name=add-feat head_commit=12345abcdef base_branch_name=master pull_num=2 pull_author=acme repo_rel_dir=mydir\n",
+			ExpOut:  "base_repo_name=basename base_repo_owner=baseowner head_repo_name=headname head_repo_owner=headowner head_branch_name=add-feat head_commit=12345abcdef base_branch_name=main pull_num=2 pull_author=acme repo_rel_dir=mydir\n",
 		},
 		{
 			Command: "echo user_name=$USER_NAME",
@@ -132,7 +132,7 @@ func TestRunStepRunner_Run(t *testing.T) {
 					Num:        2,
 					HeadBranch: "add-feat",
 					HeadCommit: "12345abcdef",
-					BaseBranch: "master",
+					BaseBranch: "main",
 					Author:     "acme",
 				},
 				User: models.User{
diff --git a/server/events/event_parser_test.go b/server/events/event_parser_test.go
index b6312a6594..09de53d548 100644
--- a/server/events/event_parser_test.go
+++ b/server/events/event_parser_test.go
@@ -360,7 +360,7 @@ func TestParseGitlabMergeEvent(t *testing.T) {
 		Num:        12,
 		HeadCommit: "d2eae324ca26242abca45d7b49d582cddb2a4f15",
 		HeadBranch: "patch-1",
-		BaseBranch: "master",
+		BaseBranch: "main",
 		State:      models.OpenPullState,
 		BaseRepo:   expBaseRepo,
 	}, pull)
@@ -440,7 +440,7 @@ func TestParseGitlabMergeEvent_Subgroup(t *testing.T) {
 		Num:        2,
 		HeadCommit: "901d9770ef1a6862e2a73ec1bacc73590abb9aff",
 		HeadBranch: "patch",
-		BaseBranch: "master",
+		BaseBranch: "main",
 		State:      models.OpenPullState,
 		BaseRepo:   expBaseRepo,
 	}, pull)
@@ -583,7 +583,7 @@ func TestParseGitlabMergeRequest(t *testing.T) {
 		Num:        8,
 		HeadCommit: "0b4ac85ea3063ad5f2974d10cd68dd1f937aaac2",
 		HeadBranch: "abc",
-		BaseBranch: "master",
+		BaseBranch: "main",
 		State:      models.OpenPullState,
 		BaseRepo:   repo,
 	}, pull)
@@ -622,7 +622,7 @@ func TestParseGitlabMergeRequest_Subgroup(t *testing.T) {
 		Num:        2,
 		HeadCommit: "901d9770ef1a6862e2a73ec1bacc73590abb9aff",
 		HeadBranch: "patch",
-		BaseBranch: "master",
+		BaseBranch: "main",
 		State:      models.OpenPullState,
 		BaseRepo:   repo,
 	}, pull)
@@ -847,7 +847,7 @@ func TestParseBitbucketCloudCommentEvent_ValidEvent(t *testing.T) {
 		HeadCommit: "e0624da46d3a",
 		URL:        "https://bitbucket.org/lkysow/atlantis-example/pull-requests/2",
 		HeadBranch: "lkysow/maintf-edited-online-with-bitbucket-1532029690581",
-		BaseBranch: "master",
+		BaseBranch: "main",
 		Author:     "557058:dc3817de-68b5-45cd-b81c-5c39d2560090",
 		State:      models.ClosedPullState,
 		BaseRepo:   expBaseRepo,
@@ -933,7 +933,7 @@ func TestParseBitbucketCloudPullEvent_ValidEvent(t *testing.T) {
 		HeadCommit: "1e69a602caef",
 		URL:        "https://bitbucket.org/lkysow/atlantis-example/pull-requests/16",
 		HeadBranch: "Luke/maintf-edited-online-with-bitbucket-1560433073473",
-		BaseBranch: "master",
+		BaseBranch: "main",
 		Author:     "557058:dc3817de-68b5-45cd-b81c-5c39d2560090",
 		State:      models.OpenPullState,
 		BaseRepo:   expBaseRepo,
@@ -1063,7 +1063,7 @@ func TestParseBitbucketServerCommentEvent_ValidEvent(t *testing.T) {
 		HeadCommit: "bfb1af1ba9c2a2fa84cd61af67e6e1b60a22e060",
 		URL:        "http://mycorp.com:7490/projects/AT/repos/atlantis-example/pull-requests/1",
 		HeadBranch: "branch",
-		BaseBranch: "master",
+		BaseBranch: "main",
 		Author:     "lkysow",
 		State:      models.OpenPullState,
 		BaseRepo:   expBaseRepo,
@@ -1145,7 +1145,7 @@ func TestParseBitbucketServerPullEvent_ValidEvent(t *testing.T) {
 		HeadCommit: "86a574157f5a2dadaf595b9f06c70fdfdd039912",
 		URL:        "http://mycorp.com:7490/projects/AT/repos/atlantis-example/pull-requests/2",
 		HeadBranch: "branch",
-		BaseBranch: "master",
+		BaseBranch: "main",
 		Author:     "lkysow",
 		State:      models.ClosedPullState,
 		BaseRepo:   expBaseRepo,
diff --git a/server/events/markdown_renderer_test.go b/server/events/markdown_renderer_test.go
index 10b478fb5c..855423a75e 100644
--- a/server/events/markdown_renderer_test.go
+++ b/server/events/markdown_renderer_test.go
@@ -181,7 +181,7 @@ $$$
 `,
 		},
 		{
-			"single successful plan with master ahead",
+			"single successful plan with main ahead",
 			command.Plan,
 			[]command.ProjectResult{
 				{
@@ -1743,7 +1743,7 @@ $$$
 `,
 		},
 		{
-			"single successful plan with master ahead",
+			"single successful plan with main ahead",
 			command.Plan,
 			[]command.ProjectResult{
 				{
diff --git a/server/events/testdata/bitbucket-cloud-comment-event.json b/server/events/testdata/bitbucket-cloud-comment-event.json
index cd71dc4eb7..f33f8f962b 100644
--- a/server/events/testdata/bitbucket-cloud-comment-event.json
+++ b/server/events/testdata/bitbucket-cloud-comment-event.json
@@ -99,7 +99,7 @@
         }
       },
       "branch": {
-        "name": "master"
+        "name": "main"
       },
       "repository": {
         "full_name": "lkysow/atlantis-example",
diff --git a/server/events/testdata/bitbucket-cloud-pull-event-created.json b/server/events/testdata/bitbucket-cloud-pull-event-created.json
index f8de61cc43..9dc2550a3c 100644
--- a/server/events/testdata/bitbucket-cloud-pull-event-created.json
+++ b/server/events/testdata/bitbucket-cloud-pull-event-created.json
@@ -83,7 +83,7 @@
         "uuid": "{94189367-116b-436a-9f77-2314b97a6067}"
       },
       "branch": {
-        "name": "master"
+        "name": "main"
       }
     },
     "created_on": "2019-06-13T13:37:58.036928+00:00",
diff --git a/server/events/testdata/bitbucket-cloud-pull-event-fulfilled.json b/server/events/testdata/bitbucket-cloud-pull-event-fulfilled.json
index aac36ec2a1..417a034bfa 100644
--- a/server/events/testdata/bitbucket-cloud-pull-event-fulfilled.json
+++ b/server/events/testdata/bitbucket-cloud-pull-event-fulfilled.json
@@ -83,7 +83,7 @@
         "uuid": "{94189367-116b-436a-9f77-2314b97a6067}"
       },
       "branch": {
-        "name": "master"
+        "name": "main"
       }
     },
     "created_on": "2019-06-13T13:37:58.036928+00:00",
diff --git a/server/events/testdata/bitbucket-cloud-pull-event-rejected.json b/server/events/testdata/bitbucket-cloud-pull-event-rejected.json
index 23399af6df..adc5b9d89d 100644
--- a/server/events/testdata/bitbucket-cloud-pull-event-rejected.json
+++ b/server/events/testdata/bitbucket-cloud-pull-event-rejected.json
@@ -83,7 +83,7 @@
         "uuid": "{94189367-116b-436a-9f77-2314b97a6067}"
       },
       "branch": {
-        "name": "master"
+        "name": "main"
       }
     },
     "created_on": "2019-02-12T16:54:45.891127+00:00",
diff --git a/server/events/testdata/bitbucket-cloud-pull-event-updated.json b/server/events/testdata/bitbucket-cloud-pull-event-updated.json
index f75d6dcc40..4c65a01daf 100644
--- a/server/events/testdata/bitbucket-cloud-pull-event-updated.json
+++ b/server/events/testdata/bitbucket-cloud-pull-event-updated.json
@@ -48,7 +48,7 @@
         }
       },
       "branch": {
-        "name": "master"
+        "name": "main"
       },
       "repository": {
         "full_name": "lkysow/atlantis-example",
@@ -209,4 +209,4 @@
     "is_private": false,
     "uuid": "{94189367-116b-436a-9f77-2314b97a6067}"
   }
-}
\ No newline at end of file
+}
diff --git a/server/events/testdata/bitbucket-server-comment-event.json b/server/events/testdata/bitbucket-server-comment-event.json
index dc5fae6d91..2621b60540 100644
--- a/server/events/testdata/bitbucket-server-comment-event.json
+++ b/server/events/testdata/bitbucket-server-comment-event.json
@@ -42,8 +42,8 @@
       }
     },
     "toRef": {
-      "id": "refs/heads/master",
-      "displayId": "master",
+      "id": "refs/heads/main",
+      "displayId": "main",
       "latestCommit": "3d1f26bc1c8eeb5ad94e247c92072717b9de6aa0",
       "repository": {
         "slug": "atlantis-example",
@@ -102,4 +102,4 @@
     "comments": [],
     "tasks": []
   }
-}
\ No newline at end of file
+}
diff --git a/server/events/testdata/bitbucket-server-get-pull.json b/server/events/testdata/bitbucket-server-get-pull.json
index c713635884..91623b6cd4 100644
--- a/server/events/testdata/bitbucket-server-get-pull.json
+++ b/server/events/testdata/bitbucket-server-get-pull.json
@@ -54,8 +54,8 @@
     }
   },
   "toRef": {
-    "id": "refs/heads/master",
-    "displayId": "master",
+    "id": "refs/heads/main",
+    "displayId": "main",
     "latestCommit": "bbc7b2a29344646ec8605be9603a0aa625a627ef",
     "repository": {
       "slug": "atlantis-example",
@@ -153,4 +153,4 @@
       }
     ]
   }
-}
\ No newline at end of file
+}
diff --git a/server/events/testdata/bitbucket-server-pull-event-created.json b/server/events/testdata/bitbucket-server-pull-event-created.json
index 1292c0a0db..e644b08c33 100644
--- a/server/events/testdata/bitbucket-server-pull-event-created.json
+++ b/server/events/testdata/bitbucket-server-pull-event-created.json
@@ -42,8 +42,8 @@
       }
     },
     "toRef": {
-      "id": "refs/heads/master",
-      "displayId": "master",
+      "id": "refs/heads/main",
+      "displayId": "main",
       "latestCommit": "3d1f26bc1c8eeb5ad94e247c92072717b9de6aa0",
       "repository": {
         "slug": "atlantis-example",
@@ -81,4 +81,4 @@
     "reviewers": [],
     "participants": []
   }
-}
\ No newline at end of file
+}
diff --git a/server/events/testdata/bitbucket-server-pull-event-declined.json b/server/events/testdata/bitbucket-server-pull-event-declined.json
index 2ed88b9a93..b4505e37ab 100644
--- a/server/events/testdata/bitbucket-server-pull-event-declined.json
+++ b/server/events/testdata/bitbucket-server-pull-event-declined.json
@@ -43,8 +43,8 @@
       }
     },
     "toRef": {
-      "id": "refs/heads/master",
-      "displayId": "master",
+      "id": "refs/heads/main",
+      "displayId": "main",
       "latestCommit": "120cff6e1452086c90689c810c15b534381ba61b",
       "repository": {
         "slug": "atlantis-example",
diff --git a/server/events/testdata/bitbucket-server-pull-event-merged.json b/server/events/testdata/bitbucket-server-pull-event-merged.json
index ed22810b1a..4e1f5e05fd 100644
--- a/server/events/testdata/bitbucket-server-pull-event-merged.json
+++ b/server/events/testdata/bitbucket-server-pull-event-merged.json
@@ -60,8 +60,8 @@
       }
     },
     "toRef": {
-      "id": "refs/heads/master",
-      "displayId": "master",
+      "id": "refs/heads/main",
+      "displayId": "main",
       "latestCommit": "120cff6e1452086c90689c810c15b534381ba61b",
       "repository": {
         "slug": "atlantis-example",
diff --git a/server/events/testdata/gitlab-get-merge-request-subgroup.json b/server/events/testdata/gitlab-get-merge-request-subgroup.json
index c1e4639fa5..92414666b9 100644
--- a/server/events/testdata/gitlab-get-merge-request-subgroup.json
+++ b/server/events/testdata/gitlab-get-merge-request-subgroup.json
@@ -7,7 +7,7 @@
   "state": "opened",
   "created_at": "2018-08-22T06:14:20.946Z",
   "updated_at": "2018-08-22T06:14:20.946Z",
-  "target_branch": "master",
+  "target_branch": "main",
   "source_branch": "patch",
   "upvotes": 0,
   "downvotes": 0,
@@ -63,4 +63,4 @@
     "start_sha": "cdf3f0f8aad6abc3c4700ad6e28936a2278a309b"
   },
   "approvals_before_merge": null
-}
\ No newline at end of file
+}
diff --git a/server/events/testdata/gitlab-get-merge-request.json b/server/events/testdata/gitlab-get-merge-request.json
index f7506ec04a..b804860415 100644
--- a/server/events/testdata/gitlab-get-merge-request.json
+++ b/server/events/testdata/gitlab-get-merge-request.json
@@ -7,7 +7,7 @@
   "state":"opened",
   "created_at":"2017-11-13T19:33:42.704Z",
   "updated_at":"2017-11-13T23:35:26.200Z",
-  "target_branch":"master",
+  "target_branch":"main",
   "source_branch":"abc",
   "upvotes":0,
   "downvotes":0,
@@ -44,4 +44,4 @@
     "human_time_estimate":null,
     "human_total_time_spent":null
   }
-}
\ No newline at end of file
+}
diff --git a/server/events/testdata/gitlab-merge-request-comment-event-subgroup.json b/server/events/testdata/gitlab-merge-request-comment-event-subgroup.json
index 9bd6e6d392..3116caf3ce 100644
--- a/server/events/testdata/gitlab-merge-request-comment-event-subgroup.json
+++ b/server/events/testdata/gitlab-merge-request-comment-event-subgroup.json
@@ -18,7 +18,7 @@
     "namespace": "sub-subgroup",
     "visibility_level": 20,
     "path_with_namespace": "lkysow-test/subgroup/sub-subgroup/atlantis-example",
-    "default_branch": "master",
+    "default_branch": "main",
     "ci_config_path": null,
     "homepage": "https://gitlab.com/lkysow-test/subgroup/sub-subgroup/atlantis-example",
     "url": "git@gitlab.com:lkysow-test/subgroup/sub-subgroup/atlantis-example.git",
@@ -79,7 +79,7 @@
     "source_branch": "patch",
     "source_project_id": 7804027,
     "state": "opened",
-    "target_branch": "master",
+    "target_branch": "main",
     "target_project_id": 7804027,
     "time_estimate": 0,
     "title": "Update main.tf",
@@ -97,7 +97,7 @@
       "namespace": "sub-subgroup",
       "visibility_level": 20,
       "path_with_namespace": "lkysow-test/subgroup/sub-subgroup/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/lkysow-test/subgroup/sub-subgroup/atlantis-example",
       "url": "git@gitlab.com:lkysow-test/subgroup/sub-subgroup/atlantis-example.git",
@@ -115,7 +115,7 @@
       "namespace": "sub-subgroup",
       "visibility_level": 20,
       "path_with_namespace": "lkysow-test/subgroup/sub-subgroup/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/lkysow-test/subgroup/sub-subgroup/atlantis-example",
       "url": "git@gitlab.com:lkysow-test/subgroup/sub-subgroup/atlantis-example.git",
@@ -137,4 +137,4 @@
     "human_total_time_spent": null,
     "human_time_estimate": null
   }
-}
\ No newline at end of file
+}
diff --git a/server/events/testdata/gitlab-merge-request-comment-event.json b/server/events/testdata/gitlab-merge-request-comment-event.json
index d92bc4d45e..8b7548e544 100644
--- a/server/events/testdata/gitlab-merge-request-comment-event.json
+++ b/server/events/testdata/gitlab-merge-request-comment-event.json
@@ -17,7 +17,7 @@
     "namespace":"Gitlab Org",
     "visibility_level":10,
     "path_with_namespace":"gitlabhq/gitlab-test",
-    "default_branch":"master",
+    "default_branch":"main",
     "homepage":"http://example.com/gitlabhq/gitlab-test",
     "url":"https://example.com/gitlabhq/gitlab-test.git",
     "ssh_url":"git@example.com:gitlabhq/gitlab-test.git",
@@ -48,7 +48,7 @@
   "merge_request": {
     "id": 7,
     "target_branch": "markdown",
-    "source_branch": "master",
+    "source_branch": "main",
     "source_project_id": 5,
     "author_id": 8,
     "assignee_id": 28,
@@ -72,7 +72,7 @@
       "namespace":"Gitlab Org",
       "visibility_level":10,
       "path_with_namespace":"gitlab-org/gitlab-test",
-      "default_branch":"master",
+      "default_branch":"main",
       "homepage":"http://example.com/gitlab-org/gitlab-test",
       "url":"https://example.com/gitlab-org/gitlab-test.git",
       "ssh_url":"git@example.com:gitlab-org/gitlab-test.git",
@@ -89,7 +89,7 @@
       "namespace":"Gitlab Org",
       "visibility_level":10,
       "path_with_namespace":"gitlabhq/gitlab-test",
-      "default_branch":"master",
+      "default_branch":"main",
       "homepage":"http://example.com/gitlabhq/gitlab-test",
       "url":"https://example.com/gitlabhq/gitlab-test.git",
       "ssh_url":"git@example.com:gitlabhq/gitlab-test.git",
@@ -97,7 +97,7 @@
     },
     "last_commit": {
       "id": "562e173be03b8ff2efb05345d12df18815438a4b",
-      "message": "Merge branch 'another-branch' into 'master'\n\nCheck in this test\n",
+      "message": "Merge branch 'another-branch' into 'main'\n\nCheck in this test\n",
       "timestamp": "2002-10-02T10:00:00-05:00",
       "url": "http://example.com/gitlab-org/gitlab-test/commit/562e173be03b8ff2efb05345d12df18815438a4b",
       "author": {
@@ -112,4 +112,4 @@
       "avatar_url": "http://www.gravatar.com/avatar/e64c7d89f26bd1972efa854d13d7dd61?s=40\u0026d=identicon"
     }
   }
-}
\ No newline at end of file
+}
diff --git a/server/events/testdata/gitlab-merge-request-event-subgroup.json b/server/events/testdata/gitlab-merge-request-event-subgroup.json
index 9b768471ab..c730c20568 100644
--- a/server/events/testdata/gitlab-merge-request-event-subgroup.json
+++ b/server/events/testdata/gitlab-merge-request-event-subgroup.json
@@ -17,7 +17,7 @@
     "namespace": "sub-subgroup",
     "visibility_level": 20,
     "path_with_namespace": "lkysow-test/subgroup/sub-subgroup/atlantis-example",
-    "default_branch": "master",
+    "default_branch": "main",
     "ci_config_path": null,
     "homepage": "https://gitlab.com/lkysow-test/subgroup/sub-subgroup/atlantis-example",
     "url": "git@gitlab.com:lkysow-test/subgroup/sub-subgroup/atlantis-example.git",
@@ -46,7 +46,7 @@
     "source_branch": "patch",
     "source_project_id": 7804027,
     "state": "opened",
-    "target_branch": "master",
+    "target_branch": "main",
     "target_project_id": 7804027,
     "time_estimate": 0,
     "title": "Update main.tf",
@@ -64,7 +64,7 @@
       "namespace": "sub-subgroup",
       "visibility_level": 20,
       "path_with_namespace": "lkysow-test/subgroup/sub-subgroup/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/lkysow-test/subgroup/sub-subgroup/atlantis-example",
       "url": "git@gitlab.com:lkysow-test/subgroup/sub-subgroup/atlantis-example.git",
@@ -82,7 +82,7 @@
       "namespace": "sub-subgroup",
       "visibility_level": 20,
       "path_with_namespace": "lkysow-test/subgroup/sub-subgroup/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/lkysow-test/subgroup/sub-subgroup/atlantis-example",
       "url": "git@gitlab.com:lkysow-test/subgroup/sub-subgroup/atlantis-example.git",
diff --git a/server/events/testdata/gitlab-merge-request-event-update-assignee.json b/server/events/testdata/gitlab-merge-request-event-update-assignee.json
index 1b506a4ea8..06b63ddd40 100644
--- a/server/events/testdata/gitlab-merge-request-event-update-assignee.json
+++ b/server/events/testdata/gitlab-merge-request-event-update-assignee.json
@@ -18,7 +18,7 @@
     "namespace": "Quan Hoang",
     "visibility_level": 0,
     "path_with_namespace": "quan.hoang/atlantis-example",
-    "default_branch": "master",
+    "default_branch": "main",
     "ci_config_path": null,
     "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
     "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -47,7 +47,7 @@
     "source_branch": "get-event-payload",
     "source_project_id": 910,
     "state_id": 1,
-    "target_branch": "master",
+    "target_branch": "main",
     "target_project_id": 910,
     "time_estimate": 0,
     "title": "Add new file",
@@ -65,7 +65,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -83,7 +83,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
diff --git a/server/events/testdata/gitlab-merge-request-event-update-description.json b/server/events/testdata/gitlab-merge-request-event-update-description.json
index 021d8c3a2c..d5e703198f 100644
--- a/server/events/testdata/gitlab-merge-request-event-update-description.json
+++ b/server/events/testdata/gitlab-merge-request-event-update-description.json
@@ -18,7 +18,7 @@
     "namespace": "Quan Hoang",
     "visibility_level": 0,
     "path_with_namespace": "quan.hoang/atlantis-example",
-    "default_branch": "master",
+    "default_branch": "main",
     "ci_config_path": null,
     "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
     "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -47,7 +47,7 @@
     "source_branch": "get-event-payload",
     "source_project_id": 910,
     "state_id": 1,
-    "target_branch": "master",
+    "target_branch": "main",
     "target_project_id": 910,
     "time_estimate": 0,
     "title": "Add new file",
@@ -65,7 +65,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -83,7 +83,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
diff --git a/server/events/testdata/gitlab-merge-request-event-update-labels.json b/server/events/testdata/gitlab-merge-request-event-update-labels.json
index b374961afd..d1607661d7 100644
--- a/server/events/testdata/gitlab-merge-request-event-update-labels.json
+++ b/server/events/testdata/gitlab-merge-request-event-update-labels.json
@@ -18,7 +18,7 @@
     "namespace": "Quan Hoang",
     "visibility_level": 0,
     "path_with_namespace": "quan.hoang/atlantis-example",
-    "default_branch": "master",
+    "default_branch": "main",
     "ci_config_path": null,
     "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
     "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -47,7 +47,7 @@
     "source_branch": "get-event-payload",
     "source_project_id": 910,
     "state_id": 1,
-    "target_branch": "master",
+    "target_branch": "main",
     "target_project_id": 910,
     "time_estimate": 0,
     "title": "Add new file",
@@ -65,7 +65,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -83,7 +83,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
diff --git a/server/events/testdata/gitlab-merge-request-event-update-mixed.json b/server/events/testdata/gitlab-merge-request-event-update-mixed.json
index e04e82ff0e..aa517171ff 100644
--- a/server/events/testdata/gitlab-merge-request-event-update-mixed.json
+++ b/server/events/testdata/gitlab-merge-request-event-update-mixed.json
@@ -18,7 +18,7 @@
     "namespace": "Quan Hoang",
     "visibility_level": 0,
     "path_with_namespace": "quan.hoang/atlantis-example",
-    "default_branch": "master",
+    "default_branch": "main",
     "ci_config_path": null,
     "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
     "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -47,7 +47,7 @@
     "source_branch": "get-event-payload",
     "source_project_id": 910,
     "state_id": 1,
-    "target_branch": "master",
+    "target_branch": "main",
     "target_project_id": 910,
     "time_estimate": 0,
     "title": "Add new file (another time)",
@@ -65,7 +65,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -83,7 +83,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
diff --git a/server/events/testdata/gitlab-merge-request-event-update-new-commit.json b/server/events/testdata/gitlab-merge-request-event-update-new-commit.json
index 0ac9facfe0..11c26b6e1f 100644
--- a/server/events/testdata/gitlab-merge-request-event-update-new-commit.json
+++ b/server/events/testdata/gitlab-merge-request-event-update-new-commit.json
@@ -18,7 +18,7 @@
     "namespace": "Quan Hoang",
     "visibility_level": 0,
     "path_with_namespace": "quan.hoang/atlantis-example",
-    "default_branch": "master",
+    "default_branch": "main",
     "ci_config_path": null,
     "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
     "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -47,7 +47,7 @@
     "source_branch": "get-event-payload",
     "source_project_id": 910,
     "state_id": 1,
-    "target_branch": "master",
+    "target_branch": "main",
     "target_project_id": 910,
     "time_estimate": 0,
     "title": "Add new file (another time)",
@@ -65,7 +65,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -83,7 +83,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
diff --git a/server/events/testdata/gitlab-merge-request-event-update-target-branch.json b/server/events/testdata/gitlab-merge-request-event-update-target-branch.json
index aae672f4ea..3ddd7a0947 100644
--- a/server/events/testdata/gitlab-merge-request-event-update-target-branch.json
+++ b/server/events/testdata/gitlab-merge-request-event-update-target-branch.json
@@ -18,7 +18,7 @@
     "namespace": "Quan Hoang",
     "visibility_level": 0,
     "path_with_namespace": "quan.hoang/atlantis-example",
-    "default_branch": "master",
+    "default_branch": "main",
     "ci_config_path": null,
     "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
     "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -65,7 +65,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -83,7 +83,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
diff --git a/server/events/testdata/gitlab-merge-request-event-update-title.json b/server/events/testdata/gitlab-merge-request-event-update-title.json
index f352bfaa46..3ad15fa89f 100644
--- a/server/events/testdata/gitlab-merge-request-event-update-title.json
+++ b/server/events/testdata/gitlab-merge-request-event-update-title.json
@@ -18,7 +18,7 @@
     "namespace": "Quan Hoang",
     "visibility_level": 0,
     "path_with_namespace": "quan.hoang/atlantis-example",
-    "default_branch": "master",
+    "default_branch": "main",
     "ci_config_path": null,
     "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
     "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -47,7 +47,7 @@
     "source_branch": "get-event-payload",
     "source_project_id": 910,
     "state_id": 1,
-    "target_branch": "master",
+    "target_branch": "main",
     "target_project_id": 910,
     "time_estimate": 0,
     "title": "Add new file",
@@ -65,7 +65,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
@@ -83,7 +83,7 @@
       "namespace": "Quan Hoang",
       "visibility_level": 0,
       "path_with_namespace": "quan.hoang/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/quan.hoang/atlantis-example",
       "url": "git@gitlab.com:quan.hoang/atlantis-example.git",
diff --git a/server/events/testdata/gitlab-merge-request-event.json b/server/events/testdata/gitlab-merge-request-event.json
index 8c27cfd34a..60be8d9726 100644
--- a/server/events/testdata/gitlab-merge-request-event.json
+++ b/server/events/testdata/gitlab-merge-request-event.json
@@ -17,7 +17,7 @@
     "namespace": "lkysow",
     "visibility_level": 20,
     "path_with_namespace": "lkysow/atlantis-example",
-    "default_branch": "master",
+    "default_branch": "main",
     "ci_config_path": null,
     "homepage": "https://gitlab.com/lkysow/atlantis-example",
     "url": "git@gitlab.com:lkysow/atlantis-example.git",
@@ -46,7 +46,7 @@
     "source_branch": "patch-1",
     "source_project_id": 4580910,
     "state": "opened",
-    "target_branch": "master",
+    "target_branch": "main",
     "target_project_id": 4580910,
     "time_estimate": 0,
     "title": "Update main.tf",
@@ -64,7 +64,7 @@
       "namespace": "sourceorg",
       "visibility_level": 20,
       "path_with_namespace": "sourceorg/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/sourceorg/atlantis-example",
       "url": "git@gitlab.com:sourceorg/atlantis-example.git",
@@ -82,7 +82,7 @@
       "namespace": "lkysow",
       "visibility_level": 20,
       "path_with_namespace": "lkysow/atlantis-example",
-      "default_branch": "master",
+      "default_branch": "main",
       "ci_config_path": null,
       "homepage": "https://gitlab.com/lkysow/atlantis-example",
       "url": "git@gitlab.com:lkysow/atlantis-example.git",
@@ -146,7 +146,7 @@
     },
     "target_branch": {
       "previous": null,
-      "current": "master"
+      "current": "main"
     },
     "target_project_id": {
       "previous": null,
diff --git a/server/events/vcs/azuredevops_client.go b/server/events/vcs/azuredevops_client.go
index c8aaa52b26..72aaf0ccdb 100644
--- a/server/events/vcs/azuredevops_client.go
+++ b/server/events/vcs/azuredevops_client.go
@@ -306,7 +306,7 @@ func (g *AzureDevopsClient) MergePull(pull models.PullRequest, pullOptions model
 		return fmt.Errorf("the user %s is not found in the organization %s", g.UserName, owner)
 	}
 
-	imageURL := "https://github.com/runatlantis/atlantis/raw/master/runatlantis.io/.vuepress/public/hero.png"
+	imageURL := "https://github.com/runatlantis/atlantis/raw/main/runatlantis.io/.vuepress/public/hero.png"
 	id := azuredevops.IdentityRef{
 		Descriptor: &descriptor,
 		ID:         userID,
diff --git a/server/events/vcs/bitbucketcloud/testdata/pull-approved-by-author.json b/server/events/vcs/bitbucketcloud/testdata/pull-approved-by-author.json
index ae0fc85812..7930cbb0bc 100644
--- a/server/events/vcs/bitbucketcloud/testdata/pull-approved-by-author.json
+++ b/server/events/vcs/bitbucketcloud/testdata/pull-approved-by-author.json
@@ -82,7 +82,7 @@
       "uuid": "{94189367-116b-436a-9f77-2314b97a6067}"
     },
     "branch": {
-      "name": "master"
+      "name": "main"
     }
   },
   "created_on": "2019-02-12T16:48:04.251028+00:00",
diff --git a/server/events/vcs/bitbucketcloud/testdata/pull-approved-multiple.json b/server/events/vcs/bitbucketcloud/testdata/pull-approved-multiple.json
index 97e819dac3..5adbea01cf 100644
--- a/server/events/vcs/bitbucketcloud/testdata/pull-approved-multiple.json
+++ b/server/events/vcs/bitbucketcloud/testdata/pull-approved-multiple.json
@@ -82,7 +82,7 @@
       "uuid": "{94189367-116b-436a-9f77-2314b97a6067}"
     },
     "branch": {
-      "name": "master"
+      "name": "main"
     }
   },
   "created_on": "2019-02-12T16:48:04.251028+00:00",
diff --git a/server/events/vcs/bitbucketcloud/testdata/pull-approved.json b/server/events/vcs/bitbucketcloud/testdata/pull-approved.json
index 9829217dc6..281103dfd8 100644
--- a/server/events/vcs/bitbucketcloud/testdata/pull-approved.json
+++ b/server/events/vcs/bitbucketcloud/testdata/pull-approved.json
@@ -82,7 +82,7 @@
       "uuid": "{94189367-116b-436a-9f77-2314b97a6067}"
     },
     "branch": {
-      "name": "master"
+      "name": "main"
     }
   },
   "created_on": "2019-02-12T16:48:04.251028+00:00",
diff --git a/server/events/vcs/bitbucketcloud/testdata/pull-unapproved.json b/server/events/vcs/bitbucketcloud/testdata/pull-unapproved.json
index 8db3811f76..3439b7cde4 100644
--- a/server/events/vcs/bitbucketcloud/testdata/pull-unapproved.json
+++ b/server/events/vcs/bitbucketcloud/testdata/pull-unapproved.json
@@ -82,7 +82,7 @@
       "uuid": "{94189367-116b-436a-9f77-2314b97a6067}"
     },
     "branch": {
-      "name": "master"
+      "name": "main"
     }
   },
   "created_on": "2019-02-12T16:48:04.251028+00:00",
diff --git a/server/events/vcs/bitbucketserver/request_validation_test.go b/server/events/vcs/bitbucketserver/request_validation_test.go
index 9b9d5228a4..4e418c3d0a 100644
--- a/server/events/vcs/bitbucketserver/request_validation_test.go
+++ b/server/events/vcs/bitbucketserver/request_validation_test.go
@@ -16,7 +16,7 @@ func TestValidateSignature(t *testing.T) {
 }
 
 func TestValidateSignature_Invalid(t *testing.T) {
-	body := `"eventKey":"pr:comment:added","date":"2018-07-24T15:10:05+0200","actor":{"name":"lkysow","emailAddress":"lkysow@gmail.com","id":1,"displayName":"Luke Kysow","active":true,"slug":"lkysow","type":"NORMAL"},"pullRequest":{"id":5,"version":0,"title":"another.tf edited online with Bitbucket","state":"OPEN","open":true,"closed":false,"createdDate":1532365427513,"updatedDate":1532365427513,"fromRef":{"id":"refs/heads/lkysow/anothertf-1532365422773","displayId":"lkysow/anothertf-1532365422773","latestCommit":"b52b8e254e956654dcdb394d0ccba9199f420427","repository":{"slug":"atlantis-example","id":1,"name":"atlantis-example","scmId":"git","state":"AVAILABLE","statusMessage":"Available","forkable":true,"project":{"key":"AT","id":1,"name":"atlantis","public":false,"type":"NORMAL"},"public":false}},"toRef":{"id":"refs/heads/master","displayId":"master","latestCommit":"0a338874369017deba7c22e99e6000932724282f","repository":{"slug":"atlantis-example","id":1,"name":"atlantis-example","scmId":"git","state":"AVAILABLE","statusMessage":"Available","forkable":true,"project":{"key":"AT","id":1,"name":"atlantis","public":false,"type":"NORMAL"},"public":false}},"locked":false,"author":{"user":{"name":"lkysow","emailAddress":"lkysow@gmail.com","id":1,"displayName":"Luke Kysow","active":true,"slug":"lkysow","type":"NORMAL"},"role":"AUTHOR","approved":false,"status":"UNAPPROVED"},"reviewers":[],"participants":[]},"comment":{"properties":{"repositoryId":1},"id":65,"version":0,"text":"comment","author":{"name":"lkysow","emailAddress":"lkysow@gmail.com","id":1,"displayName":"Luke Kysow","active":true,"slug":"lkysow","type":"NORMAL"},"createdDate":1532437805137,"updatedDate":1532437805137,"comments":[],"tasks":[]}}`
+	body := `"eventKey":"pr:comment:added","date":"2018-07-24T15:10:05+0200","actor":{"name":"lkysow","emailAddress":"lkysow@gmail.com","id":1,"displayName":"Luke Kysow","active":true,"slug":"lkysow","type":"NORMAL"},"pullRequest":{"id":5,"version":0,"title":"another.tf edited online with Bitbucket","state":"OPEN","open":true,"closed":false,"createdDate":1532365427513,"updatedDate":1532365427513,"fromRef":{"id":"refs/heads/lkysow/anothertf-1532365422773","displayId":"lkysow/anothertf-1532365422773","latestCommit":"b52b8e254e956654dcdb394d0ccba9199f420427","repository":{"slug":"atlantis-example","id":1,"name":"atlantis-example","scmId":"git","state":"AVAILABLE","statusMessage":"Available","forkable":true,"project":{"key":"AT","id":1,"name":"atlantis","public":false,"type":"NORMAL"},"public":false}},"toRef":{"id":"refs/heads/main","displayId":"main","latestCommit":"0a338874369017deba7c22e99e6000932724282f","repository":{"slug":"atlantis-example","id":1,"name":"atlantis-example","scmId":"git","state":"AVAILABLE","statusMessage":"Available","forkable":true,"project":{"key":"AT","id":1,"name":"atlantis","public":false,"type":"NORMAL"},"public":false}},"locked":false,"author":{"user":{"name":"lkysow","emailAddress":"lkysow@gmail.com","id":1,"displayName":"Luke Kysow","active":true,"slug":"lkysow","type":"NORMAL"},"role":"AUTHOR","approved":false,"status":"UNAPPROVED"},"reviewers":[],"participants":[]},"comment":{"properties":{"repositoryId":1},"id":65,"version":0,"text":"comment","author":{"name":"lkysow","emailAddress":"lkysow@gmail.com","id":1,"displayName":"Luke Kysow","active":true,"slug":"lkysow","type":"NORMAL"},"createdDate":1532437805137,"updatedDate":1532437805137,"comments":[],"tasks":[]}}`
 	secret := "mysecret"
 	sig := `sha256=ed11f92d1565a4de586727fe8260558277d58009e8957a79eb4749a7009ce083`
 	err := bitbucketserver.ValidateSignature([]byte(body), sig, []byte(secret))
diff --git a/server/events/vcs/bitbucketserver/testdata/pull-request.json b/server/events/vcs/bitbucketserver/testdata/pull-request.json
index 2f816b7eec..ee83effcf9 100644
--- a/server/events/vcs/bitbucketserver/testdata/pull-request.json
+++ b/server/events/vcs/bitbucketserver/testdata/pull-request.json
@@ -55,8 +55,8 @@
     }
   },
   "toRef": {
-    "id": "refs/heads/master",
-    "displayId": "master",
+    "id": "refs/heads/main",
+    "displayId": "main",
     "latestCommit": "59e03b9cc44e16e20741e328faaac26e377c07bf",
     "repository": {
       "slug": "example",
diff --git a/server/events/vcs/fixtures/fixtures.go b/server/events/vcs/fixtures/fixtures.go
index 5d02277f06..a6e9d2b20b 100644
--- a/server/events/vcs/fixtures/fixtures.go
+++ b/server/events/vcs/fixtures/fixtures.go
@@ -113,7 +113,7 @@ var ADPullCompleted = azuredevops.GitPullRequest{
 }
 
 var ADRepo = azuredevops.GitRepository{
-	DefaultBranch: azuredevops.String("refs/heads/master"),
+	DefaultBranch: azuredevops.String("refs/heads/main"),
 	Name:          azuredevops.String("repo"),
 	ParentRepository: &azuredevops.GitRepositoryRef{
 		Name: azuredevops.String("owner"),
@@ -279,7 +279,7 @@ var ADSelfPullCompleted = azuredevops.GitPullRequest{
 }
 
 var ADSelfRepo = azuredevops.GitRepository{
-	DefaultBranch: azuredevops.String("refs/heads/master"),
+	DefaultBranch: azuredevops.String("refs/heads/main"),
 	Name:          azuredevops.String("repo"),
 	ParentRepository: &azuredevops.GitRepositoryRef{
 		Name: azuredevops.String("owner"),
@@ -582,7 +582,7 @@ var githubAppTokenJSON = `{
 			"stargazers_count":  80,
 			"watchers_count":    80,
 			"size":              108,
-			"default_branch":    "master",
+			"default_branch":    "main",
 			"open_issues_count": 0,
 			"is_template":       true,
 			"topics": [
diff --git a/server/events/vcs/fixtures/github-commit-check-suites.json b/server/events/vcs/fixtures/github-commit-check-suites.json
index 55f3ac972e..017aee7e01 100644
--- a/server/events/vcs/fixtures/github-commit-check-suites.json
+++ b/server/events/vcs/fixtures/github-commit-check-suites.json
@@ -26,7 +26,7 @@
                         }
                     },
                     "base": {
-                        "ref": "master",
+                        "ref": "main",
                         "sha": "6f5744874b33ceb6a5c91edc91085991dbd1f61a",
                         "repo": {
                             "id": 474926944,
diff --git a/server/events/vcs/fixtures/github-pull-request.json b/server/events/vcs/fixtures/github-pull-request.json
index a0846cc499..6b37a00686 100644
--- a/server/events/vcs/fixtures/github-pull-request.json
+++ b/server/events/vcs/fixtures/github-pull-request.json
@@ -290,7 +290,7 @@
       "stargazers_count": 80,
       "watchers_count": 80,
       "size": 108,
-      "default_branch": "master",
+      "default_branch": "main",
       "open_issues_count": 0,
       "topics": [
         "octocat",
@@ -320,8 +320,8 @@
     }
   },
   "base": {
-    "label": "master",
-    "ref": "master",
+    "label": "main",
+    "ref": "main",
     "sha": "6dcb09b5b57875f334f61aebed695e2e4193db5e",
     "user": {
       "login": "octocat",
@@ -420,7 +420,7 @@
       "stargazers_count": 80,
       "watchers_count": 80,
       "size": 108,
-      "default_branch": "master",
+      "default_branch": "main",
       "open_issues_count": 0,
       "topics": [
         "octocat",
diff --git a/server/events/vcs/fixtures/github-repo.json b/server/events/vcs/fixtures/github-repo.json
index 3012d24771..21999374bb 100644
--- a/server/events/vcs/fixtures/github-repo.json
+++ b/server/events/vcs/fixtures/github-repo.json
@@ -89,7 +89,7 @@
   "forks": 0,
   "open_issues": 1,
   "watchers": 0,
-  "default_branch": "master",
+  "default_branch": "main",
   "permissions": {
     "admin": true,
     "push": true,
diff --git a/server/events/vcs/github_client_test.go b/server/events/vcs/github_client_test.go
index ee447bf88b..77e50dd85e 100644
--- a/server/events/vcs/github_client_test.go
+++ b/server/events/vcs/github_client_test.go
@@ -702,7 +702,7 @@ func TestGithubClient_PullIsMergeableWithAllowMergeableBypassApply(t *testing.T)
 						w.Write([]byte(commitJSON)) // nolint: errcheck
 					case "/api/graphql":
 						w.Write([]byte(reviewDecision)) // nolint: errcheck
-					case "/api/v3/repos/owner/repo/branches/master/protection":
+					case "/api/v3/repos/owner/repo/branches/main/protection":
 						w.Write([]byte(branchProtectionJSON)) // nolint: errcheck
 					case "/api/v3/repos/owner/repo/commits/new-topic/check-suites":
 						w.Write([]byte(checkSuites)) // nolint: errcheck
diff --git a/server/events/working_dir.go b/server/events/working_dir.go
index 6ede427ff6..2a4d4973f8 100644
--- a/server/events/working_dir.go
+++ b/server/events/working_dir.go
@@ -130,15 +130,15 @@ func (w *FileWorkspace) Clone(
 // warnDiverged returns true if we should warn the user that the branch we're
 // merging into has diverged from what we currently have checked out.
 // This matters in the case of the merge checkout strategy because after
-// cloning the repo and doing the merge, it's possible master was updated.
+// cloning the repo and doing the merge, it's possible main was updated.
 // Then users won't be getting the merge functionality they expected.
 // If there are any errors we return false since we prefer things to succeed
 // vs. stopping the plan/apply.
 func (w *FileWorkspace) warnDiverged(log logging.SimpleLogging, p models.PullRequest, headRepo models.Repo, cloneDir string) bool {
 	if !w.CheckoutMerge {
-		// It only makes sense to warn that master has diverged if we're using
+		// It only makes sense to warn that main has diverged if we're using
 		// the checkout merge strategy. If we're just checking out the branch,
-		// then it doesn't matter what's going on with master because we've
+		// then it doesn't matter what's going on with main because we've
 		// decided to always run off the branch.
 		return false
 	}
@@ -174,9 +174,9 @@ func (w *FileWorkspace) warnDiverged(log logging.SimpleLogging, p models.PullReq
 
 	hasDiverged := w.HasDiverged(log, cloneDir)
 	if hasDiverged {
-		log.Info("remote master branch is ahead and thereby has new commits, it is recommended to pull new commits")
+		log.Info("remote main branch is ahead and thereby has new commits, it is recommended to pull new commits")
 	} else {
-		log.Debug("remote master branch has no new commits")
+		log.Debug("remote main branch has no new commits")
 	}
 	return hasDiverged
 }
@@ -187,7 +187,7 @@ func (w *FileWorkspace) HasDiverged(log logging.SimpleLogging, cloneDir string)
 		// we assume false here for 'branch' strategy.
 		return false
 	}
-	// Check if remote master branch has diverged.
+	// Check if remote main branch has diverged.
 	statusUnoCmd := exec.Command("git", "status", "--untracked-files=no")
 	statusUnoCmd.Dir = cloneDir
 	outputStatusUno, err := statusUnoCmd.CombinedOutput()
diff --git a/server/events/working_dir_test.go b/server/events/working_dir_test.go
index 631f71605b..79ee18de50 100644
--- a/server/events/working_dir_test.go
+++ b/server/events/working_dir_test.go
@@ -57,20 +57,20 @@ func TestClone_CheckoutMergeNoneExisting(t *testing.T) {
 	// Initialize the git repo.
 	repoDir := initRepo(t)
 
-	// Add a commit to branch 'branch' that's not on master.
+	// Add a commit to branch 'branch' that's not on main.
 	runCmd(t, repoDir, "git", "checkout", "branch")
 	runCmd(t, repoDir, "touch", "branch-file")
 	runCmd(t, repoDir, "git", "add", "branch-file")
 	runCmd(t, repoDir, "git", "commit", "-m", "branch-commit")
 	branchCommit := runCmd(t, repoDir, "git", "rev-parse", "HEAD")
 
-	// Now switch back to master and advance the master branch by another
+	// Now switch back to main and advance the main branch by another
 	// commit.
-	runCmd(t, repoDir, "git", "checkout", "master")
-	runCmd(t, repoDir, "touch", "master-file")
-	runCmd(t, repoDir, "git", "add", "master-file")
-	runCmd(t, repoDir, "git", "commit", "-m", "master-commit")
-	masterCommit := runCmd(t, repoDir, "git", "rev-parse", "HEAD")
+	runCmd(t, repoDir, "git", "checkout", "main")
+	runCmd(t, repoDir, "touch", "main-file")
+	runCmd(t, repoDir, "git", "add", "main-file")
+	runCmd(t, repoDir, "git", "commit", "-m", "main-commit")
+	mainCommit := runCmd(t, repoDir, "git", "rev-parse", "HEAD")
 
 	// Finally, perform a merge in another branch ourselves, just so we know
 	// what the final state of the repo should be.
@@ -92,7 +92,7 @@ func TestClone_CheckoutMergeNoneExisting(t *testing.T) {
 	cloneDir, hasDiverged, err := wd.Clone(logging.NewNoopLogger(t), models.Repo{}, models.PullRequest{
 		BaseRepo:   models.Repo{},
 		HeadBranch: "branch",
-		BaseBranch: "master",
+		BaseBranch: "main",
 	}, "default")
 	Ok(t, err)
 	Equals(t, false, hasDiverged)
@@ -100,7 +100,7 @@ func TestClone_CheckoutMergeNoneExisting(t *testing.T) {
 	// Check the commits.
 	actBaseCommit := runCmd(t, cloneDir, "git", "rev-parse", "HEAD~1")
 	actHeadCommit := runCmd(t, cloneDir, "git", "rev-parse", "HEAD^2")
-	Equals(t, masterCommit, actBaseCommit)
+	Equals(t, mainCommit, actBaseCommit)
 	Equals(t, branchCommit, actHeadCommit)
 
 	// Use ls to verify the repo looks good.
@@ -114,17 +114,17 @@ func TestClone_CheckoutMergeNoReclone(t *testing.T) {
 	// Initialize the git repo.
 	repoDir := initRepo(t)
 
-	// Add a commit to branch 'branch' that's not on master.
+	// Add a commit to branch 'branch' that's not on main.
 	runCmd(t, repoDir, "git", "checkout", "branch")
 	runCmd(t, repoDir, "touch", "branch-file")
 	runCmd(t, repoDir, "git", "add", "branch-file")
 	runCmd(t, repoDir, "git", "commit", "-m", "branch-commit")
 
-	// Now switch back to master and advance the master branch by another commit.
-	runCmd(t, repoDir, "git", "checkout", "master")
-	runCmd(t, repoDir, "touch", "master-file")
-	runCmd(t, repoDir, "git", "add", "master-file")
-	runCmd(t, repoDir, "git", "commit", "-m", "master-commit")
+	// Now switch back to main and advance the main branch by another commit.
+	runCmd(t, repoDir, "git", "checkout", "main")
+	runCmd(t, repoDir, "touch", "main-file")
+	runCmd(t, repoDir, "git", "add", "main-file")
+	runCmd(t, repoDir, "git", "commit", "-m", "main-commit")
 
 	// Run the clone for the first time.
 	dataDir := t.TempDir()
@@ -140,7 +140,7 @@ func TestClone_CheckoutMergeNoReclone(t *testing.T) {
 	_, hasDiverged, err := wd.Clone(logging.NewNoopLogger(t), models.Repo{}, models.PullRequest{
 		BaseRepo:   models.Repo{},
 		HeadBranch: "branch",
-		BaseBranch: "master",
+		BaseBranch: "main",
 	}, "default")
 	Ok(t, err)
 	Equals(t, false, hasDiverged)
@@ -152,7 +152,7 @@ func TestClone_CheckoutMergeNoReclone(t *testing.T) {
 	cloneDir, hasDiverged, err := wd.Clone(logging.NewNoopLogger(t), models.Repo{}, models.PullRequest{
 		BaseRepo:   models.Repo{},
 		HeadBranch: "branch",
-		BaseBranch: "master",
+		BaseBranch: "main",
 	}, "default")
 	Ok(t, err)
 	Equals(t, false, hasDiverged)
@@ -168,7 +168,7 @@ func TestClone_CheckoutMergeNoRecloneFastForward(t *testing.T) {
 	// Initialize the git repo.
 	repoDir := initRepo(t)
 
-	// Add a commit to branch 'branch' that's not on master.
+	// Add a commit to branch 'branch' that's not on main.
 	// This will result in a fast-forwardable merge.
 	runCmd(t, repoDir, "git", "checkout", "branch")
 	runCmd(t, repoDir, "touch", "branch-file")
@@ -189,7 +189,7 @@ func TestClone_CheckoutMergeNoRecloneFastForward(t *testing.T) {
 	_, hasDiverged, err := wd.Clone(logging.NewNoopLogger(t), models.Repo{}, models.PullRequest{
 		BaseRepo:   models.Repo{},
 		HeadBranch: "branch",
-		BaseBranch: "master",
+		BaseBranch: "main",
 	}, "default")
 	Ok(t, err)
 	Equals(t, false, hasDiverged)
@@ -201,7 +201,7 @@ func TestClone_CheckoutMergeNoRecloneFastForward(t *testing.T) {
 	cloneDir, hasDiverged, err := wd.Clone(logging.NewNoopLogger(t), models.Repo{}, models.PullRequest{
 		BaseRepo:   models.Repo{},
 		HeadBranch: "branch",
-		BaseBranch: "master",
+		BaseBranch: "main",
 	}, "default")
 	Ok(t, err)
 	Equals(t, false, hasDiverged)
@@ -216,15 +216,15 @@ func TestClone_CheckoutMergeConflict(t *testing.T) {
 	// Initialize the git repo.
 	repoDir := initRepo(t)
 
-	// Add a commit to branch 'branch' that's not on master.
+	// Add a commit to branch 'branch' that's not on main.
 	runCmd(t, repoDir, "git", "checkout", "branch")
 	runCmd(t, repoDir, "sh", "-c", "echo hi >> file")
 	runCmd(t, repoDir, "git", "add", "file")
 	runCmd(t, repoDir, "git", "commit", "-m", "branch-commit")
 
-	// Add a new commit to master that will cause a conflict if branch was
+	// Add a new commit to main that will cause a conflict if branch was
 	// merged.
-	runCmd(t, repoDir, "git", "checkout", "master")
+	runCmd(t, repoDir, "git", "checkout", "main")
 	runCmd(t, repoDir, "sh", "-c", "echo conflict >> file")
 	runCmd(t, repoDir, "git", "add", "file")
 	runCmd(t, repoDir, "git", "commit", "-m", "commit")
@@ -243,7 +243,7 @@ func TestClone_CheckoutMergeConflict(t *testing.T) {
 	_, _, err := wd.Clone(logging.NewNoopLogger(t), models.Repo{}, models.PullRequest{
 		BaseRepo:   models.Repo{},
 		HeadBranch: "branch",
-		BaseBranch: "master",
+		BaseBranch: "main",
 	}, "default")
 
 	ErrContains(t, "running git merge -q --no-ff -m atlantis-merge FETCH_HEAD", err)
@@ -334,7 +334,7 @@ func TestClone_MasterHasDiverged(t *testing.T) {
 	// Atlantis checkout first PR.
 	firstPRDir := repoDir + "/first-pr"
 	runCmd(t, repoDir, "mkdir", "-p", "first-pr")
-	runCmd(t, firstPRDir, "git", "clone", "--branch", "master", "--single-branch", repoDir, ".")
+	runCmd(t, firstPRDir, "git", "clone", "--branch", "main", "--single-branch", repoDir, ".")
 	runCmd(t, firstPRDir, "git", "remote", "add", "head", repoDir)
 	runCmd(t, firstPRDir, "git", "fetch", "head", "+refs/heads/first-pr")
 	runCmd(t, firstPRDir, "git", "config", "--local", "user.email", "atlantisbot@runatlantis.io")
@@ -343,7 +343,7 @@ func TestClone_MasterHasDiverged(t *testing.T) {
 	runCmd(t, firstPRDir, "git", "merge", "-q", "--no-ff", "-m", "atlantis-merge", "FETCH_HEAD")
 
 	// Simulate second PR.
-	runCmd(t, repoDir, "git", "checkout", "master")
+	runCmd(t, repoDir, "git", "checkout", "main")
 	runCmd(t, repoDir, "git", "checkout", "-b", "second-pr")
 	runCmd(t, repoDir, "touch", "file2")
 	runCmd(t, repoDir, "git", "add", "file2")
@@ -352,7 +352,7 @@ func TestClone_MasterHasDiverged(t *testing.T) {
 	// Atlantis checkout second PR.
 	secondPRDir := repoDir + "/second-pr"
 	runCmd(t, repoDir, "mkdir", "-p", "second-pr")
-	runCmd(t, secondPRDir, "git", "clone", "--branch", "master", "--single-branch", repoDir, ".")
+	runCmd(t, secondPRDir, "git", "clone", "--branch", "main", "--single-branch", repoDir, ".")
 	runCmd(t, secondPRDir, "git", "remote", "add", "head", repoDir)
 	runCmd(t, secondPRDir, "git", "fetch", "head", "+refs/heads/second-pr")
 	runCmd(t, secondPRDir, "git", "config", "--local", "user.email", "atlantisbot@runatlantis.io")
@@ -361,10 +361,10 @@ func TestClone_MasterHasDiverged(t *testing.T) {
 	runCmd(t, secondPRDir, "git", "merge", "-q", "--no-ff", "-m", "atlantis-merge", "FETCH_HEAD")
 
 	// Merge first PR
-	runCmd(t, repoDir, "git", "checkout", "master")
+	runCmd(t, repoDir, "git", "checkout", "main")
 	runCmd(t, repoDir, "git", "merge", "first-pr")
 
-	// Copy the second-pr repo to our data dir which has diverged remote master
+	// Copy the second-pr repo to our data dir which has diverged remote main
 	runCmd(t, repoDir, "mkdir", "-p", "repos/0/")
 	runCmd(t, repoDir, "cp", "-R", secondPRDir, "repos/0/default")
 
@@ -377,7 +377,7 @@ func TestClone_MasterHasDiverged(t *testing.T) {
 	_, hasDiverged, err := wd.Clone(logging.NewNoopLogger(t), models.Repo{CloneURL: repoDir}, models.PullRequest{
 		BaseRepo:   models.Repo{CloneURL: repoDir},
 		HeadBranch: "second-pr",
-		BaseBranch: "master",
+		BaseBranch: "main",
 	}, "default")
 	Ok(t, err)
 	Equals(t, hasDiverged, true)
@@ -388,7 +388,7 @@ func TestClone_MasterHasDiverged(t *testing.T) {
 	_, hasDiverged, err = wd.Clone(logging.NewNoopLogger(t), models.Repo{}, models.PullRequest{
 		BaseRepo:   models.Repo{},
 		HeadBranch: "second-pr",
-		BaseBranch: "master",
+		BaseBranch: "main",
 	}, "default")
 	Ok(t, err)
 	Equals(t, hasDiverged, false)
@@ -407,7 +407,7 @@ func TestHasDiverged_MasterHasDiverged(t *testing.T) {
 	// Atlantis checkout first PR.
 	firstPRDir := repoDir + "/first-pr"
 	runCmd(t, repoDir, "mkdir", "-p", "first-pr")
-	runCmd(t, firstPRDir, "git", "clone", "--branch", "master", "--single-branch", repoDir, ".")
+	runCmd(t, firstPRDir, "git", "clone", "--branch", "main", "--single-branch", repoDir, ".")
 	runCmd(t, firstPRDir, "git", "remote", "add", "head", repoDir)
 	runCmd(t, firstPRDir, "git", "fetch", "head", "+refs/heads/first-pr")
 	runCmd(t, firstPRDir, "git", "config", "--local", "user.email", "atlantisbot@runatlantis.io")
@@ -416,7 +416,7 @@ func TestHasDiverged_MasterHasDiverged(t *testing.T) {
 	runCmd(t, firstPRDir, "git", "merge", "-q", "--no-ff", "-m", "atlantis-merge", "FETCH_HEAD")
 
 	// Simulate second PR.
-	runCmd(t, repoDir, "git", "checkout", "master")
+	runCmd(t, repoDir, "git", "checkout", "main")
 	runCmd(t, repoDir, "git", "checkout", "-b", "second-pr")
 	runCmd(t, repoDir, "touch", "file2")
 	runCmd(t, repoDir, "git", "add", "file2")
@@ -425,7 +425,7 @@ func TestHasDiverged_MasterHasDiverged(t *testing.T) {
 	// Atlantis checkout second PR.
 	secondPRDir := repoDir + "/second-pr"
 	runCmd(t, repoDir, "mkdir", "-p", "second-pr")
-	runCmd(t, secondPRDir, "git", "clone", "--branch", "master", "--single-branch", repoDir, ".")
+	runCmd(t, secondPRDir, "git", "clone", "--branch", "main", "--single-branch", repoDir, ".")
 	runCmd(t, secondPRDir, "git", "remote", "add", "head", repoDir)
 	runCmd(t, secondPRDir, "git", "fetch", "head", "+refs/heads/second-pr")
 	runCmd(t, secondPRDir, "git", "config", "--local", "user.email", "atlantisbot@runatlantis.io")
@@ -434,10 +434,10 @@ func TestHasDiverged_MasterHasDiverged(t *testing.T) {
 	runCmd(t, secondPRDir, "git", "merge", "-q", "--no-ff", "-m", "atlantis-merge", "FETCH_HEAD")
 
 	// Merge first PR
-	runCmd(t, repoDir, "git", "checkout", "master")
+	runCmd(t, repoDir, "git", "checkout", "main")
 	runCmd(t, repoDir, "git", "merge", "first-pr")
 
-	// Copy the second-pr repo to our data dir which has diverged remote master
+	// Copy the second-pr repo to our data dir which has diverged remote main
 	runCmd(t, repoDir, "mkdir", "-p", "repos/0/")
 	runCmd(t, repoDir, "cp", "-R", secondPRDir, "repos/0/default")
 
@@ -462,7 +462,7 @@ func TestHasDiverged_MasterHasDiverged(t *testing.T) {
 
 func initRepo(t *testing.T) string {
 	repoDir := t.TempDir()
-	runCmd(t, repoDir, "git", "init", "--initial-branch=master")
+	runCmd(t, repoDir, "git", "init", "--initial-branch=main")
 	runCmd(t, repoDir, "touch", ".gitkeep")
 	runCmd(t, repoDir, "git", "add", ".gitkeep")
 	runCmd(t, repoDir, "git", "config", "--local", "user.email", "atlantisbot@runatlantis.io")
diff --git a/server/jobs/project_command_output_handler_test.go b/server/jobs/project_command_output_handler_test.go
index 96187a65b4..604daace78 100644
--- a/server/jobs/project_command_output_handler_test.go
+++ b/server/jobs/project_command_output_handler_test.go
@@ -26,8 +26,8 @@ func createTestProjectCmdContext(t *testing.T) command.ProjectContext {
 		},
 		Pull: models.PullRequest{
 			Num:        1,
-			HeadBranch: "master",
-			BaseBranch: "master",
+			HeadBranch: "main",
+			BaseBranch: "main",
 			Author:     "test-user",
 			HeadCommit: "234r232432",
 		},
diff --git a/testdrive/testdrive.go b/testdrive/testdrive.go
index 14816e5a9d..53a839e414 100644
--- a/testdrive/testdrive.go
+++ b/testdrive/testdrive.go
@@ -252,7 +252,7 @@ tunnels:
 	// Create a new pr in the example repo.
 	colorstring.Println("=> creating a new pull request")
 	s.Start()
-	pullRequestURL, err := githubClient.CreatePullRequest(githubUsername, terraformExampleRepo, "example", "master")
+	pullRequestURL, err := githubClient.CreatePullRequest(githubUsername, terraformExampleRepo, "example", "main")
 	if err != nil {
 		return errors.Wrapf(err, "creating new pull request for repo %s/%s", githubUsername, terraformExampleRepo)
 	}
diff --git a/testing/README.md b/testing/README.md
index dc732aa515..4c36e35cd0 100644
--- a/testing/README.md
+++ b/testing/README.md
@@ -3,9 +3,9 @@
 The Docker image used by the tests is `runatlantis/testing-env`. It's built by the Dockerfie
 in this directory.
 
-The image is automatically built by Docker Hub on merges to `master`.
+The image is automatically built by Docker Hub on merges to `main`.
 
-To update the image, create a pull request that updates the Dockerfile and get it merged to `master`.
+To update the image, create a pull request that updates the Dockerfile and get it merged to `main`.
 
 Wait until the build at https://hub.docker.com/repository/docker/runatlantis/testing-env/builds finishes
 and then scroll to the bottom to find output like: