She was 95.
O'Hara died in her sleep at her home in Boise, Idaho, said Johnny Nicoletti, her longtime manager.
"She passed peacefully surrounded by her loving family as they celebrated her life listening to music from her favorite movie, 'The Quiet Man,'" said a statement from her family.
"As an actress, Maureen O'Hara brought unyielding strength and sudden sensitivity to every role she played. Her characters were feisty and fearless, just as she was in real life. She was also proudly Irish and spent her entire lifetime sharing her heritage and the wonderful culture of the Emerald Isle with the world," said a family biography.
During her movie heyday, she became known as the Queen of Technicolor because of the camera's love affair with her vivid hair, pale complexion and fiery nature.
After her start in Hollywood with "Hunchback" and some minor films at RKO, she was borrowed by 20th Century Fox to play the beautiful young daughter in the 1941 saga of a coal-mining family, "How Green Was My Valley."
"How Green Was My Valley" went on to win five Oscars including best picture and best director for John Ford, beating out Orson Welles and "Citizen Kane" among others.
The popularity of "How Green Was My Valley" confirmed O'Hara's status as a Hollywood star.
RKO and Fox shared her contract, and her most successful films were made at Fox.
They included "Miracle on 34th Street," the classic 1947 Christmas story in which O'Hara was little Natalie Wood's skeptical mother and among those charmed by Edmund Gwenn as a man who believed he was Santa Claus.
Other films included the costume drama "The Foxes of Harrow" (Rex Harrison, 1947); the comedy "Sitting Pretty" (Clifton Webb, 1948); and the sports comedy "Father Was a Fullback" (Fred MacMurray, 1949).
