Maria de Lourdes Villiers Farrow was born February 9, 1945, in Los Angeles, California, the third child and eldest daughter of Australian film director John Farrow and his second wife, the Irish actress Maureen O'Sullivan. She is one of seven children, with older brothers Michael Damien, Patrick, younger brother John Charles, and younger sisters Prudence, Stephanie, and Tisa. Her godparents were director George Cukor and columnist Louella Parsons.
Farrow was raised in Beverly Hills, California, in a strict Catholic household. She was described by her family as an eccentric and imaginative child, and would occasionally put on performances with "toy daggers and fake blood" for passing celebrity tour buses. Aged two, she made her film debut in a short documentary, Unusual Occupations: Film Tot Holiday (1947). Farrow attended Catholic parochial schools in Los Angeles for her primary education. At nine years old, she contracted polio during an outbreak in Los Angeles County reportedly affecting 500 people. She was placed in an isolation ward for three weeks and later said the experience "marked the end of [her] childhood."
In 1958, the Farrow family temporarily relocated to Spain, where her father was filming John Paul Jones (1959). Farrow, then age 13, made a brief uncredited appearance in the film. In September 1958, Farrow and her sister Prudence were sent to attend Marymount International School London, a convent-operated boarding school in Surrey, England while her father completed post-production on John Paul Jones in London.
On October 28, 1958, Farrow's eldest brother Michael died in a plane crash near Pacoima, California while a member of the United States Marine Corps Reserve. After his burial, Farrow returned to boarding school in Surrey. Her family temporarily lived in the London Park Lane Hotel before renting a home in Chelsea. Farrow's father began drinking heavily, which strained the marriage. In her memoir, Farrow recalls witnessing violent arguments between her parents while visiting their Chelsea residence.
When Farrow was 16, she returned with her family to the United States and continued her education at an all-girls Catholic school in Los Angeles, Marymount High School. (She is among its most famous alumnae.) Farrow subsequently studied at Bard College.
During this time, her parents were struggling financially and her mother relocated to New York City to act in Broadway productions. Farrow's father remained in California, where he died the following year of a heart attack. Farrow was 17 years old.
The family was left with little money after her father's death, prompting Farrow to begin working to help support herself and her siblings. She initially found work as a fashion model before being cast as a replacement in a New York stage production of The Importance of Being Earnest.
