diff --git a/.github/workflows/gambit.yml b/.github/workflows/gambit.yml
index ae2a9f09e..fac59a8a9 100644
--- a/.github/workflows/gambit.yml
+++ b/.github/workflows/gambit.yml
@@ -2,6 +2,7 @@ name: Gambit mutation testing
 
 on:
   workflow_dispatch:
+  pull_request:
 
 jobs:
   run-mutation-tests: