What is the Queen's surname?

Question

have you never wondered that?

Its always the royal family this royal family that but hey?

Answer 1

Windsor is the usual name used, but Mountbatten-Windsor is also in use for authorising some activities, assuming the person asking the question is referring to the queen in England. Like all the royals, she has a personal name for use with some personal matters, finance, banking and property deals when she acts in her private capacity in England or abroad.