Billy Barty (October 25, 1924–December 23, 2000), born William John Bertanzetti, was an American film actor.

Billy Barty began performing at three, and began making pictures in 1933. He played Mickey Rooney (I)'s little brother in the "Mickey McGuire" comedy shorts series. He was equally adept in both comedy and drama, and generally gives an added zest to any production he is associated with. He founded the Little People of America in 1957, and the Billy Barty Foundation in 1975. He possessed an immense talent and energetic charm that added a much needed shot in the arm to many shows and films.