diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index b6a44ef17..67fe28c49 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -121,6 +121,7 @@ jobs:
   mutation-tests:
     name: Run mutation tests
     runs-on: ubuntu-22.04
+    if: github.ref == 'refs/heads/main' && github.event_name != 'pull_request'
 
     steps:
       - name: Checkout repository