What is the last name of England's royal family?

Well, being the royal family, they have very little use for a last name, since everyone knows who they are, according to the family’s official Web site. However, the queen signs official documents “Elizabeth R.” The R stands for Regina, which means “queen.” (Regina is not one of her given names; she was baptized Elizabeth Alexandra Mary.) George V used the family name Windsor during World War I. When Princess Elizabeth (the current queen) served as a subaltern in the Auxiliary Territorial Service during World War II, she was called Elizabeth Windsor. Elizabeth married Prince Philip of Greece, whose family name was Mountbatten, and eventually she decreed that most of her descendants would be called Mountbatten-Windsor. Princess Anne used this name in 1973 when she married Captain Mark Phillips. Officially, however, the name Mountbatten-Windsor does not apply to princes or princesses. Any British royal who is styled “Royal Highness” — including Prince Charles and his sons — belongs to the house of Windsor.