What was Queen Elizabeth's II last name before becoming queen?

Answer 1

As Elizabeth II was the daughter of King George VI, and as she chose her own name as her regnal name, her name before assuming the throne was, as it is after, Elizabeth Alexandra Mary.

Do note that the Royal Family does not have a surname, thus that is her complete name.

Answer 2

Queen Elizabeth's surname was Windsor.

Her family's surname was Saxe-Coburg-Gotha until 1917 when they changed it to Windsor to sound non-German (the British people were anti-German then as it was WWI).

Members of the British Royal Family do not have surnames. They are the descendants of the house of Windsor but this is not the same as holding a surname. However, as you posted this Question in the "Elizabeth I" category I assume you mean the first Queen Elizabeth. Elizabeth I was a member of the House of Tudor but, as with Elizabeth II this does not constitute a surname

Answer 3

Her name was Elizabeth WINDSOR