Lillian Hellman's play was inspired by the 1809 true story of two Scottish school teachers whose lives were destroyed when one of their students accused them of engaging in a lesbian relationship. At the time, the mention of homosexuality on stage was illegal in New York State, but authorities chose to overlook its subject matter when the Broadway production was acclaimed by the critics.
Because the Hays Code in effect at the time would never permit a film to focus on or even hint at lesbianism, Samuel Goldwyn was the only producer interested in purchasing the rights. He signed Hellman to adapt her play for the screen, and the playwright changed the lie about the two school teachers being lovers into a rumor that one of them had slept with the other's fiancé. Because the Production Code refused to allow Goldman to use the play's original title, it was changed to The Lie, and then These Three.
By the time Wyler was ready to film the remake, the Hays Code had been liberalized to allow screenwriter John Michael Hayes to restore the original nature of the lie. Aside from having Martha hang rather than shoot herself as she had in the play, he remained faithful to Hellman's work, retaining substantial portions of her dialogue.
In the 1996 documentary film The Celluloid Closet, Shirley MacLaine said she and Audrey Hepburn never talked about their characters' alleged homosexuality. She also claimed Wyler cut some scenes hinting at her character's love for Hepburn because of concerns about critical reaction to the film.
The film was James Garner's first after suing Warner Bros. to win his release from the television series Maverick. Wyler broke an unofficial blacklist of the actor by casting him, and Garner steadily appeared in films and television shows over the following decades, including immediately playing the lead in four different major movies released in 1963.
Miriam Hopkins, who portrays Lily Mortar in the remake, appeared as Martha in These Three.
The film's location shooting was done at the historic Shadow Ranch, in present day West Hills of the western San Fernando Valley.