diff --git a/.github/workflows/labels.yml b/.github/workflows/labels.yml
index 11417b9e72bc..de92fd998808 100644
--- a/.github/workflows/labels.yml
+++ b/.github/workflows/labels.yml
@@ -7,7 +7,8 @@ on:
       - main
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
+  # Avoid github.ref, which is always main for the pull_request_target trigger.
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number }}
   cancel-in-progress: true
 
 permissions: