diff --git a/src/ol/observable.js b/src/ol/observable.js
index d5e409e550..f27b917006 100644
--- a/src/ol/observable.js
+++ b/src/ol/observable.js
@@ -61,6 +61,18 @@ ol.Observable.prototype.changed = function() {
  */
 
 
+/**
+ * Dispatches an event and calls all listeners listening for events
+ * of this type. The event parameter can either be a string or an
+ * Object with a `type` property.
+ *
+ * @param {goog.events.EventLike} event Event object.
+ * @function
+ * @api
+ */
+ol.Observable.prototype.dispatchEvent;
+
+
 /**
  * Get the version number for this object.  Each time the object is modified,
  * its version number will be incremented.