diff --git a/.github/workflows/ruby.yml b/.github/workflows/ruby.yml
index 13bf38a..0485576 100644
--- a/.github/workflows/ruby.yml
+++ b/.github/workflows/ruby.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        ruby-version: ['2.0', '2.1', '2.2', '2.3', '2.4', '2.5', '2.6', '2.7', '3.0', '3.1', '3.2', '3.3', '3.4']
+        ruby-version: ['2.0', '2.1', '2.2', '2.3', '2.4', '2.5', '2.6', '2.7', '3.0', '3.1', '3.2', '3.3', '3.4', '4.0']
         channel: ['stable']
         os: ['ubuntu-latest']