Tatum Beatrice O'Neal was born on November 5, 1963 in Los Angeles, California, and is an American actress best known for her film work as a child actress in the 1970s.

O'Neal was born into the motion picture family of actor Ryan O'Neal (of mostly Irish ancestry) and actress Joanna Moore (of English descent). Her mother died in 1997 of lung cancer after a successful career in which she had appeared in such movies as Touch of Evil.

In her autobiography called A Paper Life, Tatum O'Neal alleged that she had been the victim of child molestation by a male friend of her father's. Tatum also alleges physical and emotional abuse from her father, much of which she attributes to drug use.

In 1974, Tatum O'Neal became the youngest person ever to receive the Best Supporting Actress for her performance in Paper Moon. This controversial movie which also featured her real-life father as a con-man, portrayed young Tatum as a child in the company of a crook who was being further tutored in a life of crime and corruption. The motion picture was financed by Herbert W. Armstrong's Ambassador International Cultural Foundation.

Other movies starring Tatum O'Neal include The Bad News Bears, Nickelodeon (both 1976), International Velvet (1978), and Little Darlings (1980).

In 1986, O'Neal wed tennis superstar John McEnroe, and the couple had three children. Following their divorce in 1992, she took up residence in New York City. McEnroe, who in 1997 married musician Patty Smyth, has custody of his three children with O'Neal.