diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index 335bd80109..3f59b815b3 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -6,6 +6,8 @@ on:
 
 jobs:
   build:
+    if: github.repository == 'backstage/backstage' # prevent running on forks
+
     runs-on: ubuntu-latest
 
     strategy: