diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index d43ec29..642ea62 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-22.04
     strategy:
       matrix:
-        ruby: ["3.4", "3.3", "3.2", "3.1", "3.0", "2.7", "2.6"]
+        ruby: ["4.0", "3.4", "3.3", "3.2", "3.1", "3.0", "2.7", "2.6"]
     name: Ruby ${{ matrix.ruby }}
     steps:
       - uses: actions/checkout@v3