diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4e06b9a2..9f0ba9bd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -33,8 +33,8 @@ jobs:
         - { os: ubuntu-latest  , ruby: jruby-9.2 } # Ruby 2.5
         - { os: ubuntu-latest  , ruby: jruby-9.3 } # Ruby 2.7
         - { os: ubuntu-latest  , ruby: jruby-9.4 } # Ruby 3.1
-        # - { os: macos-latest   , ruby: truffleruby }
-        # - { os: ubuntu-latest  , ruby: truffleruby }
+        - { os: macos-latest   , ruby: truffleruby-head }
+        - { os: ubuntu-latest  , ruby: truffleruby-head }
         exclude:
         - { os: macos-14, ruby: 2.3 }
         - { os: macos-14, ruby: 2.4 }