diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6c95ce2..9cd5c24 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -4,6 +4,12 @@ on:
   pull_request:
   workflow_dispatch:
 
+# Group runs by workflow and PR/ref.
+# When a new run starts for the same PR, branch, or tag, cancel the older one.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
 jobs:
   test:
     uses: bats-core/.github/.github/workflows/test.yml@v1