All About Eve is a 1950 American drama film written and directed by Joseph L. Mankiewicz, and produced by Darryl F. Zanuck. It is based on the 1946 short story (and subsequent 1949 radio drama) "The Wisdom of Eve" by Mary Orr, although Orr does not receive a screen credit.

The film stars Bette Davis as Margo Channing, a highly regarded but aging Broadway star, and Anne Baxter as Eve Harrington, an ambitious young fan who maneuvers herself into Channing's life, ultimately threatening Channing's career and her personal relationships. The film co-stars George Sanders, Celeste Holm, Gary Merrill, and Hugh Marlowe, and features Thelma Ritter, Marilyn Monroe in one of her earliest roles, Gregory Ratoff, Barbara Bates and Walter Hampden.

All About Eve held its world premiere in New York City on October 13, 1950. Highly praised by critics at the time of its release, it received a record 14 nominations at the 23rd Academy Awards, becoming the only film in Oscar history to receive four female acting nominations (Davis and Baxter as Best Actress, Holm and Ritter as Best Supporting Actress). It went on to win six awards, including Best Picture, as well as Best Director and Best Adapted Screenplay, Mankiewicz's second consecutive wins in both categories.

Widely considered as among the greatest films of all time, in 1990, All About Eve became one of 25 films selected that year for preservation in the United States Library of Congress's National Film Registry, deemed "culturally, historically, or aesthetically significant". The film was ranked No. 16 on AFI's 1998 list of the 100 best American films.

At the Sarah Siddons Award ceremony honoring rising actress Eve Harrington, narration from acerbic theatre critic Addison DeWitt introduces the attendees and hints that there is more to Eve's story.

The narration switches to Karen Richards, wife of playwright Lloyd Richards. She recalls the previous October, when she introduced Eve to aging Broadway star Margo Channing, who was starring in a play written by Lloyd. Eve tells Karen, Lloyd, and Margo's maid Birdie that she followed Margo's last theatrical tour to New York City after seeing her perform in San Francisco. She tells of her impoverished childhood and losing her husband in the South Pacific during World War II, and, moved by Eve's story, Margo takes her into her home as her assistant. Eve quickly manipulates her way into Margo's life as both secretary and adoring fan.

Margo is also concerned about her romantic relationship with Bill Sampson, eight years her junior, who is directing a film in California. Without telling Margo, Eve arranges a midnight long-distance phone call from Margo to Bill on his birthday. Eve hopes the unexpected late call will show Bill that Margo forgot his birthday and also sends her own greeting. Margo realizes that Eve set her up and asks producer Max Fabian to hire Eve at his office to get her away from Bill; instead, Eve has Karen convince Fabian to make Eve Margo's understudy without Margo's knowledge.

As Margo's irritation grows, Karen sympathizes with Eve, believing that Margo is overdramatizing her resentment towards her. Hoping to humble Margo, Karen conspires for her to miss a performance so Eve can perform in her place. Eve secretly invites the city's theater critics, including Addison, to attend the performance. Eve's performance is a triumph. Later that night, Eve attempts to seduce Bill, but he rejects her.