diff --git a/get-changed-paths.sh b/get-changed-paths.sh
index 746737ca..efe967e7 100755
--- a/get-changed-paths.sh
+++ b/get-changed-paths.sh
@@ -10,7 +10,7 @@ INPUT_SEPARATOR="${INPUT_SEPARATOR//$'\r'/'%0D'}"
 GITHUB_OUTPUT=${GITHUB_OUTPUT:-""}
 DIFF="..."
 
-if [[ -z $GITHUB_BASE_REF ]]; then
+if [[ -z $GITHUB_BASE_REF || "$GITHUB_EVENT_HEAD_REPO_FORK" == "true" ]]; then
   DIFF=".."
 fi