diff --git a/.github/workflows/rspec.yml b/.github/workflows/rspec.yml
index 49028ad..dd3b818 100644
--- a/.github/workflows/rspec.yml
+++ b/.github/workflows/rspec.yml
@@ -5,7 +5,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["2.7", "3.1", "3.2", "3.3", "3.4", ruby-head]
+        ruby: ["2.7", "3.1", "3.2", "3.3", "3.4", "4.0", "ruby-head"]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3