diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 4fd7f19..047187b 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, windows-latest, macOS-latest]
+        os: [ubuntu-latest, windows-latest, macos-latest]
     steps:
       - uses: actions/checkout@v2
       - name: Environment Information