diff --git a/externs/polymer-externs.js b/externs/polymer-externs.js
index 12bd2d0384..0a86620b69 100644
--- a/externs/polymer-externs.js
+++ b/externs/polymer-externs.js
@@ -100,6 +100,9 @@ PolymerTelemetry.dumpRegistrations;;
 /** @type {PolymerTelemetry} */
 Polymer.telemetry;
 
+/** @type {string} */
+Polymer.version;
+
 // nb. This is explicitly 'var', as Closure Compiler checks that this is the case.
 /**
  * @constructor