Story of O (French: Histoire d'O, IPA: [istwaʁ do]) is a 1975 erotic drama film directed by Just Jaeckin from a screenplay by Sébastien Japrisot, based on the 1954 novel of the same name by Pauline Réage.

A young woman fashion photographer, known only as O, is taken by her lover René to Château Roissy, where she is subject to various sexual and sadomasochistic acts as part of her training to serve the members of the club.

She leaves Roissy wearing an iron ring as a sign of her initiation and indicator to men in the society that she is a sex slave.

At Sir Stephen's direction, O is sent to an all-female country house in Samois, run by a woman named Anne-Marie, where she undergoes further beatings and training in submission.

Later Sir Stephen and O visit the commander's home in Brittany for a party, where O is treated as a visual spectacle, wearing nothing but chains and an owl mask.