diff --git a/.github/workflows/benchmark.yml b/.github/workflows/benchmark.yml
index b62624612..9a948d038 100644
--- a/.github/workflows/benchmark.yml
+++ b/.github/workflows/benchmark.yml
@@ -15,6 +15,11 @@ on:
 
   workflow_dispatch:
 
+concurrency:
+  # Group by PR to cancel outdated runs; unique run IDs keep non-PR runs independent.
+  group: ${{ github.workflow }}-${{ github.event_name }}-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
+
 jobs:
   benchmark:
     runs-on: ${{ matrix.os }}