diff --git a/src/ol/object.js b/src/ol/object.js
index 4bca4e75ca..cbef3af6c6 100644
--- a/src/ol/object.js
+++ b/src/ol/object.js
@@ -10,6 +10,7 @@ goog.provide('ol.ObjectEventType');
 
 goog.require('goog.array');
 goog.require('goog.events');
+goog.require('goog.events.Event');
 goog.require('goog.functions');
 goog.require('goog.object');
 goog.require('ol.Observable');
@@ -19,11 +20,34 @@ goog.require('ol.Observable');
  * @enum {string}
  */
 ol.ObjectEventType = {
+  BEFORECHANGE: 'beforechange',
   CHANGE: 'change'
 };
 
 
 
+/**
+ * Object representing a property change event.
+ *
+ * @param {string} type The event type.
+ * @param {string} key The property name.
+ * @extends {goog.events.Event}
+ * @constructor
+ */
+ol.ObjectEvent = function(type, key) {
+  goog.base(this, type);
+
+  /**
+   * The name of the property whose value is changing.
+   * @type {string}
+   */
+  this.key = key;
+
+};
+goog.inherits(ol.ObjectEvent, goog.events.Event);
+
+
+
 /**
  * @constructor
  * @param {ol.Object} target
@@ -331,7 +355,7 @@ ol.Object.prototype.notify = function(key) {
 ol.Object.prototype.notifyInternal_ = function(key) {
   var eventType = ol.Object.getChangeEventType(key);
   this.dispatchEvent(eventType);
-  this.dispatchEvent(ol.ObjectEventType.CHANGE);
+  this.dispatchEvent(new ol.ObjectEvent(ol.ObjectEventType.CHANGE, key));
 };
 
 
@@ -342,6 +366,7 @@ ol.Object.prototype.notifyInternal_ = function(key) {
  * @todo stability experimental
  */
 ol.Object.prototype.set = function(key, value) {
+  this.dispatchEvent(new ol.ObjectEvent(ol.ObjectEventType.BEFORECHANGE, key));
   var accessors = ol.Object.getAccessors(this);
   if (accessors.hasOwnProperty(key)) {
     var accessor = accessors[key];
diff --git a/test/spec/ol/object.test.js b/test/spec/ol/object.test.js
index 1c59d6f273..9a53c6d40f 100644
--- a/test/spec/ol/object.test.js
+++ b/test/spec/ol/object.test.js
@@ -121,7 +121,11 @@ describe('ol.Object', function() {
 
     it('dispatches generic change events to bound objects', function() {
       o.notify('k');
-      expect(listener2).to.be.called();
+      expect(listener2.calledOnce).to.be(true);
+      var args = listener2.firstCall.args;
+      expect(args).to.have.length(1);
+      var event = args[0];
+      expect(event.key).to.be('k');
     });
 
     it('dispatches events to bound objects', function() {
@@ -157,7 +161,25 @@ describe('ol.Object', function() {
 
     it('dispatches generic change events to object', function() {
       o.set('k', 1);
-      expect(listener2).to.be.called();
+      expect(listener2.calledOnce).to.be(true);
+      var args = listener2.firstCall.args;
+      expect(args).to.have.length(1);
+      var event = args[0];
+      expect(event.key).to.be('k');
+    });
+
+    it('dispatches beforechange events to object', function() {
+      o.set('k', 1);
+
+      var oldValue;
+      var beforeListener = sinon.spy(function(event) {
+        oldValue = o2.get(event.key);
+      });
+      o.on('beforechange', beforeListener);
+
+      o.set('k', 2);
+      expect(beforeListener.calledOnce).to.be(true);
+      expect(oldValue).to.be(1);
     });
 
     it('dispatches events to bound object', function() {
@@ -175,8 +197,32 @@ describe('ol.Object', function() {
 
     it('dispatches generic change events to object bound to', function() {
       o2.set('k', 2);
-      expect(listener2).to.be.called();
+      expect(listener2.calledOnce).to.be(true);
+      var args = listener2.firstCall.args;
+      expect(args).to.have.length(1);
+      var event = args[0];
+      expect(event.key).to.be('k');
     });
+
+    it('dispatches beforechange before changing bound objects', function() {
+      o2.set('k', 1);
+
+      var oldValue;
+      var beforeListener = sinon.spy(function(event) {
+        oldValue = o2.get(event.key);
+      });
+      o.on('beforechange', beforeListener);
+
+      o2.set('k', 2);
+      expect(beforeListener.calledOnce).to.be(true);
+      var args = listener2.firstCall.args;
+      expect(args).to.have.length(1);
+      var event = args[0];
+      expect(event.key).to.be('k');
+
+      expect(oldValue).to.be(1);
+    });
+
   });
 
   describe('bind', function() {