diff --git a/.github/workflows/prune-harbor.yaml b/.github/workflows/prune-harbor.yaml
index 9b823a947..1e5223754 100644
--- a/.github/workflows/prune-harbor.yaml
+++ b/.github/workflows/prune-harbor.yaml
@@ -12,6 +12,7 @@ concurrency: prune-harbor
 jobs:
   prune-harbor:
     name: Prune ${{ matrix.name }} harbor registry
+    if: github.repository == 'jupyterhub/mybinder.org-deploy'
     runs-on: ubuntu-22.04
 
     strategy: