diff --git a/Gruntfile.js b/Gruntfile.js
index ada6baa4b..0f5c32ba7 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -60,7 +60,8 @@ module.exports = function( grunt ) {
 				files: {
 					"qunit": "qunit/qunit",
 					"require.js": "requirejs/require.js",
-					"sinon/fake_timers.js": "sinon/lib/sinon/util/fake_timers.js"
+					"sinon/fake_timers.js": "sinon/lib/sinon/util/fake_timers.js",
+					"sinon/timers_ie.js": "sinon/lib/sinon/util/timers_ie.js"
 				}
 			}
 		},
diff --git a/test/index.html b/test/index.html
index ce19c4d5e..bfadff7f8 100644
--- a/test/index.html
+++ b/test/index.html
@@ -17,6 +17,7 @@
 	<script src="libs/qunit/qunit.js"></script>
 	<script src="libs/require.js"></script>
 	<script src="libs/sinon/fake_timers.js"></script>
+	<script src="libs/sinon/timers_ie.js"></script>
 	<!-- See testinit for the list of tests -->
 	<script src="data/testinit.js"></script>
 
diff --git a/test/libs/sinon/timers_ie.js b/test/libs/sinon/timers_ie.js
new file mode 100644
index 000000000..7903a0e78
--- /dev/null
+++ b/test/libs/sinon/timers_ie.js
@@ -0,0 +1,27 @@
+/*global sinon, setTimeout, setInterval, clearTimeout, clearInterval, Date*/
+/**
+ * Helps IE run the fake timers. By defining global functions, IE allows
+ * them to be overwritten at a later point. If these are not defined like
+ * this, overwriting them will result in anything from an exception to browser
+ * crash.
+ *
+ * If you don't require fake timers to work in IE, don't include this file.
+ *
+ * @author Christian Johansen (christian@cjohansen.no)
+ * @license BSD
+ *
+ * Copyright (c) 2010-2013 Christian Johansen
+ */
+function setTimeout() {}
+function clearTimeout() {}
+function setInterval() {}
+function clearInterval() {}
+function Date() {}
+
+// Reassign the original functions. Now their writable attribute
+// should be true. Hackish, I know, but it works.
+setTimeout = sinon.timers.setTimeout;
+clearTimeout = sinon.timers.clearTimeout;
+setInterval = sinon.timers.setInterval;
+clearInterval = sinon.timers.clearInterval;
+Date = sinon.timers.Date;
diff --git a/test/unit/effects.js b/test/unit/effects.js
index 4f75dddf2..b3916b4a5 100644
--- a/test/unit/effects.js
+++ b/test/unit/effects.js
@@ -5,18 +5,21 @@ if ( !jQuery.fx ) {
 	return;
 }
 
-var off = jQuery.fx.off;
+var off = jQuery.fx.off,
+	oldNow = jQuery.now;
 
 module("effects", {
 	setup: function() {
 		this.clock = sinon.useFakeTimers( 505877050 );
 		this._oldInterval = jQuery.fx.interval;
 		jQuery.fx.interval = 10;
-		jQuery.now = Date.now;
+		jQuery.now = function() {
+			return +( new Date() );
+		};
 	},
 	teardown: function() {
 		this.clock.restore();
-		jQuery.now = Date.now;
+		jQuery.now = oldNow;
 		jQuery.fx.stop();
 		jQuery.fx.interval = this._oldInterval;
 		jQuery.fx.off = off;