diff --git a/tests/unit/slider/slider.html b/tests/unit/slider/slider.html
index 0142b5e6bd..38520c0730 100644
--- a/tests/unit/slider/slider.html
+++ b/tests/unit/slider/slider.html
@@ -9,6 +9,7 @@
 	<script src="../../../external/qunit/qunit.js"></script>
 	<script src="../../../external/jquery-simulate/jquery.simulate.js"></script>
 	<script src="../testsuite.js"></script>
+	<script src="../../../external/qunit-assert-classes/qunit-assert-classes.js"></script>
 	<script>
 	TestHelpers.loadResources({
 		css: [ "core", "slider" ],
diff --git a/tests/unit/slider/slider_common.js b/tests/unit/slider/slider_common.js
index a72071f793..d43869bf0c 100644
--- a/tests/unit/slider/slider_common.js
+++ b/tests/unit/slider/slider_common.js
@@ -2,7 +2,11 @@ TestHelpers.commonWidgetTests( "slider", {
 	defaults: {
 		animate: false,
 		cancel: "input,textarea,button,select,option",
-		classes: {},
+		classes: {
+			"ui-slider": "ui-corner-all",
+			"ui-slider-handle": "ui-corner-all",
+			"ui-slider-range": "ui-corner-all ui-widget-header"
+		},
 		delay: 0,
 		disabled: false,
 		distance: 0,
diff --git a/tests/unit/slider/slider_core.js b/tests/unit/slider/slider_core.js
index 3649bded03..fa86b2df46 100644
--- a/tests/unit/slider/slider_core.js
+++ b/tests/unit/slider/slider_core.js
@@ -12,6 +12,18 @@ function handle() {
 // Slider Tests
 module( "slider: core" );
 
+test( "markup structure", function( assert ) {
+	expect( 4 );
+	var element = $( "<div>" ).slider({ range: true }),
+		handle = element.find( "span" ),
+		range = element.find( "div" );
+
+	assert.hasClasses( element, "ui-slider ui-slider-horizontal ui-widget ui-widget-content" );
+	assert.hasClasses( range, "ui-slider-range ui-widget-header" );
+	assert.hasClasses( handle[ 0 ], "ui-slider-handle" );
+	assert.hasClasses( handle[ 1 ], "ui-slider-handle" );
+});
+
 test( "keydown HOME on handle sets value to min", function() {
 	expect( 2 );
 	element = $( "<div></div>" );
diff --git a/ui/slider.js b/ui/slider.js
index fceb367f31..7d8619d43f 100644
--- a/ui/slider.js
+++ b/ui/slider.js
@@ -39,6 +39,14 @@ return $.widget( "ui.slider", $.ui.mouse, {
 
 	options: {
 		animate: false,
+		classes: {
+			"ui-slider": "ui-corner-all",
+			"ui-slider-handle": "ui-corner-all",
+
+			// Note: ui-widget-header isn't the most fittingly semantic framework class for this
+			// element, but worked best visually with a variety of themes
+			"ui-slider-range": "ui-corner-all ui-widget-header"
+		},
 		distance: 0,
 		max: 100,
 		min: 0,
@@ -68,12 +76,8 @@ return $.widget( "ui.slider", $.ui.mouse, {
 		this._mouseInit();
 		this._calculateNewMax();
 
-		this.element
-			.addClass( "ui-slider" +
-				" ui-slider-" + this.orientation +
-				" ui-widget" +
-				" ui-widget-content" +
-				" ui-corner-all");
+		this._addClass( "ui-slider ui-slider-" + this.orientation,
+			"ui-widget ui-widget-content" );
 
 		this._refresh();
 		this._setOption( "disabled", this.options.disabled );
@@ -91,8 +95,8 @@ return $.widget( "ui.slider", $.ui.mouse, {
 	_createHandles: function() {
 		var i, handleCount,
 			options = this.options,
-			existingHandles = this.element.find( ".ui-slider-handle" ).addClass( "ui-state-default ui-corner-all" ),
-			handle = "<span class='ui-slider-handle ui-state-default ui-corner-all' tabindex='0'></span>",
+			existingHandles = this.element.find( ".ui-slider-handle" ),
+			handle = "<span tabindex='0'></span>",
 			handles = [];
 
 		handleCount = ( options.values && options.values.length ) || 1;
@@ -108,6 +112,8 @@ return $.widget( "ui.slider", $.ui.mouse, {
 
 		this.handles = existingHandles.add( $( handles.join( "" ) ).appendTo( this.element ) );
 
+		this._addClass( this.handles, "ui-slider-handle", "ui-state-default" );
+
 		this.handle = this.handles.eq( 0 );
 
 		this.handles.each(function( i ) {
@@ -116,8 +122,7 @@ return $.widget( "ui.slider", $.ui.mouse, {
 	},
 
 	_createRange: function() {
-		var options = this.options,
-			classes = "";
+		var options = this.options;
 
 		if ( options.range ) {
 			if ( options.range === true ) {
@@ -131,24 +136,22 @@ return $.widget( "ui.slider", $.ui.mouse, {
 			}
 
 			if ( !this.range || !this.range.length ) {
-				this.range = $( "<div></div>" )
+				this.range = $( "<div>" )
 					.appendTo( this.element );
 
-				classes = "ui-slider-range" +
-				// note: this isn't the most fittingly semantic framework class for this element,
-				// but worked best visually with a variety of themes
-				" ui-widget-header ui-corner-all";
+				this._addClass( this.range, "ui-slider-range" );
 			} else {
-				this.range.removeClass( "ui-slider-range-min ui-slider-range-max" )
-					// Handle range switching from true to min/max
-					.css({
-						"left": "",
-						"bottom": ""
-					});
-			}
+				this._removeClass( this.range, "ui-slider-range-min ui-slider-range-max" );
 
-			this.range.addClass( classes +
-				( ( options.range === "min" || options.range === "max" ) ? " ui-slider-range-" + options.range : "" ) );
+				// Handle range switching from true to min/max
+				this.range.css({
+					"left": "",
+					"bottom": ""
+				});
+			}
+			if ( options.range === "min" || options.range === "max" ) {
+				this._addClass( this.range, "ui-slider-range-" + options.range );
+			}
 		} else {
 			if ( this.range ) {
 				this.range.remove();
@@ -170,14 +173,6 @@ return $.widget( "ui.slider", $.ui.mouse, {
 			this.range.remove();
 		}
 
-		this.element
-			.removeClass( "ui-slider" +
-				" ui-slider-horizontal" +
-				" ui-slider-vertical" +
-				" ui-widget" +
-				" ui-widget-content" +
-				" ui-corner-all" );
-
 		this._mouseDestroy();
 	},
 
@@ -218,9 +213,8 @@ return $.widget( "ui.slider", $.ui.mouse, {
 
 		this._handleIndex = index;
 
-		closestHandle
-			.addClass( "ui-state-active" )
-			.focus();
+		this._addClass( closestHandle, null, "ui-state-active" );
+		closestHandle.focus();
 
 		offset = closestHandle.offset();
 		mouseOverHandle = !$( event.target ).parents().addBack().is( ".ui-slider-handle" );
@@ -254,7 +248,7 @@ return $.widget( "ui.slider", $.ui.mouse, {
 	},
 
 	_mouseStop: function( event ) {
-		this.handles.removeClass( "ui-state-active" );
+		this._removeClass( this.handles, null, "ui-state-active" );
 		this._mouseSliding = false;
 
 		this._stop( event, this._handleIndex );
@@ -451,7 +445,7 @@ return $.widget( "ui.slider", $.ui.mouse, {
 		}
 
 		if ( key === "disabled" ) {
-			this.element.toggleClass( "ui-state-disabled", !!value );
+			this._toggleClass( null, "ui-state-disabled", !!value );
 		}
 
 		this._super( key, value );
@@ -459,9 +453,8 @@ return $.widget( "ui.slider", $.ui.mouse, {
 		switch ( key ) {
 			case "orientation":
 				this._detectOrientation();
-				this.element
-					.removeClass( "ui-slider-horizontal ui-slider-vertical" )
-					.addClass( "ui-slider-" + this.orientation );
+				this._removeClass( "ui-slider-horizontal ui-slider-vertical" )
+					._addClass( "ui-slider-" + this.orientation );
 				this._refreshValue();
 
 				// Reset positioning from previous orientation
@@ -659,7 +652,7 @@ return $.widget( "ui.slider", $.ui.mouse, {
 					event.preventDefault();
 					if ( !this._keySliding ) {
 						this._keySliding = true;
-						$( event.target ).addClass( "ui-state-active" );
+						this._addClass( $( event.target ), null, "ui-state-active" );
 						allowed = this._start( event, index );
 						if ( allowed === false ) {
 							return;
@@ -716,7 +709,7 @@ return $.widget( "ui.slider", $.ui.mouse, {
 				this._keySliding = false;
 				this._stop( event, index );
 				this._change( event, index );
-				$( event.target ).removeClass( "ui-state-active" );
+				this._removeClass( $( event.target ), null, "ui-state-active" );
 			}
 		}
 	}