Margaret O'Brien (born January 15, 1937 in San Diego, California) is an Academy Award-winning American film actress, and although her career was brief, was one of the most highly regarded child actors in cinema history.

Born Angela Maxine O'Brien, her father, a circus performer, died months after her birth; Margaret's mother, Gladys Flores, was a well-known flamenco dancer who often performed with her sister Marissa, also a dancer. Margaret is of half-Irish and half-Spanish ancestry.

She made her first film appearance in Babes on Broadway (1941) at the age of four, but it was the following year that her first major role brought her widespread attention. As a five-year-old in Journey for Margaret (1942), O'Brien won wide praise for her convincing acting style. By 1943, she was considered a big enough star to have a cameo appearance in the all-star military show finale of Thousands Cheer.

She played a young French girl, and spoke and sang all her dialogue with a French accent, in Jane Eyre (1944). Arguably her most memorable role was as "Tootie" in Meet Me in St. Louis (1944), opposite Judy Garland. O'Brien had by this time added singing and dancing to her achievements and was rewarded with an Academy Juvenile Award the following year. Her other successes included The Canterville Ghost (1944), Our Vines Have Tender Grapes (1945), and the first sound version of The Secret Garden (1949), but she was unable to make the transition to adult roles.

A 1946 Looney Tunes short, Book Revue, placed a caricature of O'Brien in the role of Little Red Riding Hood.

She played the role of Betsy Stauffer, a small town nurse, in "The Incident of the Town in Terror" on television's Rawhide.

Margaret later shed her child star image in 1958 by appearing on the cover of Life Magazine with the caption "The Girl's Grown"'. O'Brien's acting roles as an adult have been few and far between, mostly in small independent films. However, she does do occasional interviews, mostly for the Turner Classic Movies cable network. One rare television outing was as a guest star on the popular Marcus Welby, M.D. in the early 1970s, reuniting Margaret with her The Canterville Ghost co-star Robert Young.

She has been married twice, to Harold Allen, Jr. from 1959 to 1968, and later to Roy Thorsen. The later marriage produced her only child, Mara Tolene Thorsen, born in 1977. Margaret is that rare child star who did not wind up fighting off poverty and addictions in later life. All her memories of her child star days are happy ones, except for working with the difficult Wallace Beery, who would pinch her to the point where crew members would have to protect her.

O'Brien has two stars on the Hollywood Walk of Fame for Motion Pictures at 6608 Hollywood Boulevard, and for television at 1620 Vine St. In 2006, she was presented with a Lifetime Achievement Award by the SunDeis Film Festival at Brandeis University.

Born Angela Maxine O'Brien on January 15, 1937 in San Diego, California. Her film debut was one-minute shot in MGM's Babes on Broadway (1941). Her big moment came when she was cast in Journey for Margaret (1942). This film shot her into instant stardom and also resulted in Angela changing her name to Margaret. Throughout the 1940s Margaret was a major child star. Her unforgettable performance as "Tootie" in Vincente Minnelli's Meet Me in St. Louis (1944) won her an Academy Award as "Outstanding Child Actress" of her day. She gave brilliant performances in such films as Canterville Ghost, The (1944), Our Vines Have Tender Grapes (1945), Secret Garden, The (1949) and Little Women (1949). By the early 1950s Margaret had made a mint for MGM and earned a personal fortune. But like most other child stars, she failed in her bid to graduate into adolescent roles and in 1951 she retired from the screen. She remained active on TV and on the dinner-theater circuit. In 1979 she began a stint as a civilian aide for Southern California to Secretary of the Army Clifford Alexander.