diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 20c6048a3..e637ed889 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,6 +20,10 @@ defaults:
   run:
     shell: bash
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
 jobs:
   # Test crates on their minimum Rust versions and nightly Rust.
   test: