diff --git a/externs/webcomponents-externs.js b/externs/webcomponents-externs.js
index 4a1987d54d..df0f46b8f0 100644
--- a/externs/webcomponents-externs.js
+++ b/externs/webcomponents-externs.js
@@ -33,7 +33,7 @@ let ShadyDOM = {
 
 window.ShadyDOM = ShadyDOM;
 
-let WebComponents = {};
+var WebComponents = {};
 window.WebComponents = WebComponents;
 
 /** @type {Element} */