diff --git a/.github/workflows/mirror-main-to-master.yml b/.github/workflows/mirror-main-to-master.yml
index 087095d..368b208 100644
--- a/.github/workflows/mirror-main-to-master.yml
+++ b/.github/workflows/mirror-main-to-master.yml
@@ -9,6 +9,7 @@ on:
 jobs:
   mirror-main-to-master:
     runs-on: ubuntu-latest
+    if: github.repository == 'github/vscode-codeql-starter'
 
     steps:
       - uses: actions/checkout@v2