diff --git a/changelog/upgrade-notes.md b/changelog/upgrade-notes.md
index a850ab4bdb..11643de713 100644
--- a/changelog/upgrade-notes.md
+++ b/changelog/upgrade-notes.md
@@ -41,6 +41,7 @@ The following methods did get the optional this (i.e. opt_this) arguments remove
 
 * Collection#forEach
 * geom/LineString#forEachSegment
+* Observable#on, #once, #un
 
 ### v4.6.0
 
diff --git a/src/ol/Observable.js b/src/ol/Observable.js
index 785bd45036..cf69ec5123 100644
--- a/src/ol/Observable.js
+++ b/src/ol/Observable.js
@@ -91,23 +91,22 @@ _ol_Observable_.prototype.getRevision = function() {
  * Listen for a certain type of event.
  * @param {string|Array.<string>} type The event type or array of event types.
  * @param {function(?): ?} listener The listener function.
- * @param {Object=} opt_this The object to use as `this` in `listener`.
  * @return {ol.EventsKey|Array.<ol.EventsKey>} Unique key for the listener. If
  *     called with an array of event types as the first argument, the return
  *     will be an array of keys.
  * @api
  */
-_ol_Observable_.prototype.on = function(type, listener, opt_this) {
+_ol_Observable_.prototype.on = function(type, listener) {
   if (Array.isArray(type)) {
     var len = type.length;
     var keys = new Array(len);
     for (var i = 0; i < len; ++i) {
-      keys[i] = _ol_events_.listen(this, type[i], listener, opt_this);
+      keys[i] = _ol_events_.listen(this, type[i], listener);
     }
     return keys;
   } else {
     return _ol_events_.listen(
-        this, /** @type {string} */ (type), listener, opt_this);
+        this, /** @type {string} */ (type), listener);
   }
 };
 
@@ -116,23 +115,22 @@ _ol_Observable_.prototype.on = function(type, listener, opt_this) {
  * Listen once for a certain type of event.
  * @param {string|Array.<string>} type The event type or array of event types.
  * @param {function(?): ?} listener The listener function.
- * @param {Object=} opt_this The object to use as `this` in `listener`.
  * @return {ol.EventsKey|Array.<ol.EventsKey>} Unique key for the listener. If
  *     called with an array of event types as the first argument, the return
  *     will be an array of keys.
  * @api
  */
-_ol_Observable_.prototype.once = function(type, listener, opt_this) {
+_ol_Observable_.prototype.once = function(type, listener) {
   if (Array.isArray(type)) {
     var len = type.length;
     var keys = new Array(len);
     for (var i = 0; i < len; ++i) {
-      keys[i] = _ol_events_.listenOnce(this, type[i], listener, opt_this);
+      keys[i] = _ol_events_.listenOnce(this, type[i], listener);
     }
     return keys;
   } else {
     return _ol_events_.listenOnce(
-        this, /** @type {string} */ (type), listener, opt_this);
+        this, /** @type {string} */ (type), listener);
   }
 };
 
@@ -141,18 +139,16 @@ _ol_Observable_.prototype.once = function(type, listener, opt_this) {
  * Unlisten for a certain type of event.
  * @param {string|Array.<string>} type The event type or array of event types.
  * @param {function(?): ?} listener The listener function.
- * @param {Object=} opt_this The object which was used as `this` by the
- * `listener`.
  * @api
  */
-_ol_Observable_.prototype.un = function(type, listener, opt_this) {
+_ol_Observable_.prototype.un = function(type, listener) {
   if (Array.isArray(type)) {
     for (var i = 0, ii = type.length; i < ii; ++i) {
-      _ol_events_.unlisten(this, type[i], listener, opt_this);
+      _ol_events_.unlisten(this, type[i], listener);
     }
     return;
   } else {
-    _ol_events_.unlisten(this, /** @type {string} */ (type), listener, opt_this);
+    _ol_events_.unlisten(this, /** @type {string} */ (type), listener);
   }
 };
 export default _ol_Observable_;
diff --git a/test/spec/ol/observable.test.js b/test/spec/ol/observable.test.js
index d3480caae4..b750cb0a24 100644
--- a/test/spec/ol/observable.test.js
+++ b/test/spec/ol/observable.test.js
@@ -41,15 +41,6 @@ describe('ol.Observable', function() {
       expect(listener.callCount).to.be(2);
     });
 
-    it('accepts an optional `this` arg for the listener', function() {
-      var thisArg = {};
-      observable.on('foo', listener, thisArg);
-
-      observable.dispatchEvent('foo');
-      expect(listener.calledOnce).to.be(true);
-      expect(listener.calledOn(thisArg)).to.be(true);
-    });
-
     it('returns a listener key', function() {
       var key = observable.on('foo', listener);
 
@@ -106,15 +97,6 @@ describe('ol.Observable', function() {
       expect(listener.callCount).to.be(2);
     });
 
-    it('accepts an optional `this` arg for the listener', function() {
-      var thisArg = {};
-      observable.once('foo', listener, thisArg);
-
-      observable.dispatchEvent('foo');
-      expect(listener.calledOnce).to.be(true);
-      expect(listener.calledOn(thisArg)).to.be(true);
-    });
-
     it('returns a listener key', function() {
       var key = observable.once('foo', listener);
 
@@ -141,24 +123,6 @@ describe('ol.Observable', function() {
       expect(listener.calledOnce).to.be(true);
     });
 
-    it('accepts a `this` arg', function() {
-      var thisArg = {};
-      observable.on('foo', listener, thisArg);
-
-      observable.dispatchEvent('foo');
-      expect(listener.calledOnce).to.be(true);
-
-      // will not unregister without the same thisArg
-      observable.un('foo', listener);
-      observable.dispatchEvent('foo');
-      expect(listener.callCount).to.be(2);
-
-      // properly unregister by providing the same thisArg
-      observable.un('foo', listener, thisArg);
-      observable.dispatchEvent('foo');
-      expect(listener.callCount).to.be(2);
-    });
-
   });
 
   describe('ol.Observable.unByKey()', function() {