diff --git a/lib/jira/resource/user.rb b/lib/jira/resource/user.rb
index fc2705d3..7cb64b41 100644
--- a/lib/jira/resource/user.rb
+++ b/lib/jira/resource/user.rb
@@ -13,7 +13,7 @@ class User < JIRA::Base
       MAX_RESULTS = 1000
 
       def self.singular_path(client, key, prefix = '/')
-        collection_path(client, prefix) + '?username=' + key
+        collection_path(client, prefix) + '?accountId=' + key
       end
 
       # Cannot retrieve more than 1,000 users through the api, please see: https://jira.atlassian.com/browse/JRASERVER-65089
diff --git a/spec/integration/user_spec.rb b/spec/integration/user_spec.rb
index efe66e1f..b7275f4c 100644
--- a/spec/integration/user_spec.rb
+++ b/spec/integration/user_spec.rb
@@ -5,13 +5,26 @@
     let(:client) { client }
     let(:site_url) { site_url }
 
-    let(:key) { 'admin' }
+    let(:key) { '1234567890abcdef01234567' }
 
     let(:expected_attributes) do
       {
-        'self' => 'http://localhost:2990/jira/rest/api/2/user?username=admin',
-        'name' => key,
-        'emailAddress' => 'admin@example.com'
+        'id' => '1234567890abcdef01234567',
+        'self' => 'http://localhost:2990/jira/rest/api/2/user?accountId=1234567890abcdef01234567',
+        'name' => 'admin',
+        'emailAddress' => 'admin@example.com',
+        'avatarUrls' => {
+          '16x16' => 'http://localhost:2990/jira/secure/useravatar?size=small&avatarId=10122',
+          '48x48' => 'http://localhost:2990/jira/secure/useravatar?avatarId=10122'
+        },
+        'displayName' => 'admin',
+        'active' => true,
+        'timeZone' => 'Pacific/Auckland',
+        'groups' => {
+          'size' => 3,
+          'items' => []
+        },
+        'expand' => 'groups'
       }
     end
 
diff --git a/spec/jira/resource/user_factory_spec.rb b/spec/jira/resource/user_factory_spec.rb
index e1d60ab7..c94cbe43 100644
--- a/spec/jira/resource/user_factory_spec.rb
+++ b/spec/jira/resource/user_factory_spec.rb
@@ -10,7 +10,7 @@
   describe '#myself' do
     let(:response) do
       instance_double(
-        'Response', body: get_mock_response('user_username=admin.json')
+        'Response', body: get_mock_response('user_accountId=1234567890abcdef01234567.json')
       )
     end
 
diff --git a/spec/mock_responses/user_username=admin.json b/spec/mock_responses/user_accountId=1234567890abcdef01234567.json
similarity index 73%
rename from spec/mock_responses/user_username=admin.json
rename to spec/mock_responses/user_accountId=1234567890abcdef01234567.json
index a14c4d27..82d63fbb 100644
--- a/spec/mock_responses/user_username=admin.json
+++ b/spec/mock_responses/user_accountId=1234567890abcdef01234567.json
@@ -1,5 +1,6 @@
 {
-  "self": "http://localhost:2990/jira/rest/api/2/user?username=admin",
+  "id": "1234567890abcdef01234567",
+  "self": "http://localhost:2990/jira/rest/api/2/user?accountId=1234567890abcdef01234567",
   "name": "admin",
   "emailAddress": "admin@example.com",
   "avatarUrls": {