diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index 2efe51e..3423f0c 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -18,7 +18,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['2.7', '3.0', '3.4']
+        ruby-version: ['2.7', '3.0', '3.4', '4.0']
     steps:
     - uses: actions/checkout@v2
     - name: Set up Ruby
@@ -33,7 +33,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: ['2.7', '3.0', '3.4']
+        ruby-version: ['2.7', '3.0', '3.4', '4.0']
     env:
       GEM_VERSIONS: min
     steps: