diff --git a/.circleci/config.yml b/.circleci/config.yml
index 99e648f..13f32ba 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -60,3 +60,7 @@ workflows:
     jobs:
       - build:
           context: org-global
+          filters:
+            branches:
+              # Forked pull requests have CIRCLE_BRANCH set to pull/XXX
+              ignore: /pull\/[0-9]+/