Add the ability to click the legend's items in a similar way like the series 'items. For the time being the following workaround can be used: JavaScript: <script> function pageLoad() { //Attach the legendItemClick event on pageLoad: var chart = $find("<%=RadHtmlChart1.ClientID%>")._chartObject.bind("legendItemClick", OnLegendClicked); } //The following function toggles the visibility of the clicked series from the legend function OnLegendClicked(e) { //Get a reference to the chart and the target axis var chart = e.sender; var targetAxisName = e.series.axis; var numValueAxes = chart.options.valueAxis.length; //Iterate through the y-axes and toggle the visibility of the axis that corresponds to the clicked series from the legend for (var i = 0; i < numValueAxes; i++) { var currValueAxisName = chart.options.valueAxis[i].name; if (currValueAxisName == targetAxisName) { chart.options.valueAxis[i].visible = !chart.options.valueAxis[i].visible; } } } </script> ASPX: <telerik:RadHtmlChart ID="RadHtmlChart1" runat="server" Width="600px" Height="400px"> <PlotArea> <Series> <telerik:LineSeries AxisName="axis1" Name="Series1"> <SeriesItems> <telerik:CategorySeriesItem Y="30" /> <telerik:CategorySeriesItem Y="10" /> <telerik:CategorySeriesItem Y="20" /> </SeriesItems> </telerik:LineSeries> <telerik:LineSeries AxisName="axis2" Name="Series2"> <SeriesItems> <telerik:CategorySeriesItem Y="3000" /> <telerik:CategorySeriesItem Y="1000" /> <telerik:CategorySeriesItem Y="2000" /> </SeriesItems> </telerik:LineSeries> <telerik:LineSeries AxisName="axis2" Name="Series3"> <SeriesItems> <telerik:CategorySeriesItem Y="3500" /> <telerik:CategorySeriesItem Y="1500" /> <telerik:CategorySeriesItem Y="2500" /> </SeriesItems> </telerik:LineSeries> </Series> <YAxis Name="axis1" MinValue="0" MaxValue="30"> </YAxis> <AdditionalYAxes> <telerik:AxisY Name="axis2" MinValue="900" MaxValue="3600"></telerik:AxisY> </AdditionalYAxes> </PlotArea> </telerik:RadHtmlChart>