When thinking about it, you have to admit to yourself that unless you're British, you really don't know the last name of Prince William and the royal family, amirite?

He has a last name?

tudor? habsburg? using my high school history knowledge based on popular dynasties... i ruled out Chang

Ummm I think its castro

The princes don't really have one. They use Mountbatten-Windsor sometimes, and William and Harry use Wales for military purposes.

Proud Prince Harry fan right here :)

Mountbatton-Windsor?

windsor?? i think... i'm from canada

MOUNTBATTEN-WINDSOR

Their last name is Winsor, like the town :)
But then again i am english.