Tina Cole (born August 4, 1943) is an American actress and singer. She is best known for her role as Katie Miller Douglas on the 1960s sitcom My Three Sons (1967–72), but she previously had a recurring role as Sunny Day in the detective series Hawaiian Eye (1963). She was also a member of the Four King Cousins, a subgroup of the King Family Singers. In 1963 she played the minor (uncredited) role of Ruth Stewart in Palm Springs Weekend, a spring break party film set in Palm Springs, California.