diff --git a/scripts/modules/request.js b/scripts/modules/request.js
index 37f3ac0d7b..31a7a4a1f8 100644
--- a/scripts/modules/request.js
+++ b/scripts/modules/request.js
@@ -40,6 +40,9 @@ module.exports = {
                     response = { statusCode: httpRequest.status };
                 }
                 callback(error, response, optionalCallbackParameter);
+
+                // Break circular reference to httpRequest so the engine can garbage collect it.
+                httpRequest.onreadystatechange = null;
             }
         };
         if (typeof options === 'string') {