diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 817e65e..2aae1ac 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -7,8 +7,10 @@ jobs:
     name: build (${{ matrix.ruby }} / ${{ matrix.os }})
     strategy:
       matrix:
-        ruby: [ '3.0', 2.7, 2.6, 2.1, head ]
+        ruby: [ '3.0', 2.7, 2.6, 2.1, head, truffleruby-head ]
         os: [ ubuntu-latest, macos-latest, windows-latest ]
+        exclude:
+        - { os: windows-latest, ruby: truffleruby-head }
     runs-on: ${{ matrix.os }}
     steps:
     - name: git config