diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d84e36488..b85fca8f8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -29,7 +29,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: [ "1.9.3", "2.0.0", 2.1, 2.3, 2.4, 2.5, 2.6, 2.7, "3.0", 3.1, 3.2, 3.3, jruby-9.2, jruby-9.3, jruby-9.4, truffleruby-head ]
+        ruby: [ "1.9.3", "2.0.0", 2.1, 2.3, 2.4, 2.5, 2.6, 2.7, "3.0", 3.1, 3.2, 3.3, 3.4, jruby-9.2, jruby-9.3, jruby-9.4, truffleruby-head ]
     name: ${{ matrix.ruby }}
     env:
       BUNDLE_GEMFILE: .ci.gemfile