There are two ways to assign tooltips to RadButton, namely setting the ToolTipText property of the ButtonElement, or as in most of the RadControls by using the ToolTipTextNeeded event of RadButton. It is necessary the ShowItemToolTips property to be set to true which is the default value.
Setting the ToolTipText property
this.radButton1.ButtonElement.ToolTipText = "I am a button";
Me.radButton1.ButtonElement.ToolTipText = "I am a button"
Setting tool tips in the ToolTipTextNeeded event
private void radButton1_ToolTipTextNeeded(object sender, Telerik.WinControls.ToolTipTextNeededEventArgs e)
e.ToolTipText = "Click me";
Private Sub radButton1_ToolTipTextNeeded(sender As Object, e As Telerik.WinControls.ToolTipTextNeededEventArgs)
e.ToolTipText = "Click me"
The ToolTipTextNeeded event has higher priority and overrides the tool tips set in the ToolTipText property.