diff --git a/lib/events.js b/lib/events.js
index 26e0f061933..ad3ce726c74 100644
--- a/lib/events.js
+++ b/lib/events.js
@@ -89,6 +89,8 @@ EventEmitter.prototype.once = function(type, listener) {
     self.removeListener(type, g);
     listener.apply(this, arguments);
   });
+
+  return this;
 };
 
 EventEmitter.prototype.removeListener = function(type, listener) {