The ribbon is a complex control that has many parts so a single background really doesn't apply to the entire control. I'm not sure which specific area of the ribbon you are trying to change but the brushes that are used within the ribbon are exposed as resourcekeys (defined in the RibbonBrushKeys class) so you can change them as needed. You can also look at the default styles shipped with the product to see what resource keys are used in case the name of the resourcekey isn't clear. Please be aware that there are visual appearance guidelines set forth in the Office UI Guidelines that you must adhere to when using the ribbon.