A system and method that allows Web Part developers to customize Extensible Web Part Menus by programmatically adding, deleting, or modifying the commands that appear in the Extensible Web Part Menu. The customization may be performed by the Web Part developer either through a portal page on a server platform or on a client platform. Once the customization to the Extensible Web Part Menu is complete, the Web Part renders the customized Extensible Web Part Menu in a manner that is completely integrated into the rest of the Web Part on the portal page.