diff --git a/framework/core/src/Foundation/Site.php b/framework/core/src/Foundation/Site.php
index 1a45d55c8..1de5d4c1e 100644
--- a/framework/core/src/Foundation/Site.php
+++ b/framework/core/src/Foundation/Site.php
@@ -63,6 +63,12 @@ class Site
             return [];
         }
 
-        return array_flatten(require $extenderFile);
+        $extenders = require $extenderFile;
+
+        if (! is_array($extenders)) {
+            return [];
+        }
+
+        return array_flatten($extenders);
     }
 }