diff --git a/tests/unit/dialog/dialog_options.js b/tests/unit/dialog/dialog_options.js
index 264c2fb6ee1..e581796da33 100644
--- a/tests/unit/dialog/dialog_options.js
+++ b/tests/unit/dialog/dialog_options.js
@@ -446,4 +446,36 @@ test("width", function() {
 	el.remove();
 });
 
+test("zIndex", function() {
+	expect(9);
+
+	el = $('<div></div>').dialog( { autoOpen: false } );
+		equals(dlg().css( 'zIndex' ), 1000, "default zIndex");
+		el.dialog("open");
+		equals(dlg().css( 'zIndex' ), $.ui.dialog.maxZ, "default zIndex");
+	el.remove();
+
+	el = $('<div></div>').dialog();
+		equals(dlg().css( 'zIndex' ), $.ui.dialog.maxZ, "default zIndex");
+	el.remove();
+
+	// The z-index will be 1 higher than requested if 'moveToTop' gets called, such as when 'autoOpen' is true.
+	newZIndex = $.ui.dialog.maxZ + 2932;
+	el = $('<div></div>').dialog({zIndex: newZIndex });
+		equals(dlg().css('zIndex'), newZIndex + 1, "explicit zIndex");
+		equals( el.dialog( 'option', 'zIndex' ), newZIndex, 'get works for zIndex' );
+		equals( newZIndex + 1, $.ui.dialog.maxZ, '$.ui.dialog.maxZ is updated to the new value' );
+		
+		el.dialog('option', 'zIndex', 1748);
+		equals(dlg().css('zIndex'), 1748, 'explicit zIndex after init');
+		equals( el.dialog( 'option', 'zIndex' ), 1748 );
+	el.remove();
+	
+	// At the moment, an explicit zIndex option lower than $.ui.dialog.maxZ will be ignored since 'open' calls
+	// 'moveToTop'. Is this the desired behavior?
+	el = $('<div></div>').dialog({zIndex: 1584 });
+		equals(dlg().css('zIndex'), $.ui.dialog.maxZ, "explicit zIndex at instantiation below $.ui.dialog.maxZ is ignored");
+	el.remove();
+});
+
 })(jQuery);
diff --git a/ui/jquery.ui.dialog.js b/ui/jquery.ui.dialog.js
index 1f959a837b6..d47feb8d74d 100644
--- a/ui/jquery.ui.dialog.js
+++ b/ui/jquery.ui.dialog.js
@@ -605,6 +605,25 @@ $.widget("ui.dialog", {
 				$( ".ui-dialog-title", self.uiDialogTitlebar )
 					.html( "" + ( value || "&#160;" ) );
 				break;
+			case "zIndex":
+				if ( value > $.ui.dialog.maxZ ) {
+					// Increment the 'maxZ' counters when this dialog is currently visible
+					if ( self.isOpen() ) {
+						$.ui.dialog.maxZ = value;
+						
+						if ( self.overlay ) {
+							$.ui.dialog.overlay.maxZ = $.ui.dialog.maxZ;
+							$.ui.dialog.maxZ += 1;
+						}
+					}
+					
+					value = $.ui.dialog.maxZ;
+				}
+				
+				self.overlay && self.overlay.$el.css( "z-index", value - 1 );
+				uiDialog.css( "z-index", value );
+				
+				break;
 		}
 
 		this._super( key, value );