Meg Tilly and Colin Firth fell in love while they were making the film. A year later they had a son together.
Michelle Pfeiffer was offered the role of the Marquise de Merteuil at the same time she was offered the role as Madame de Tourvel in Dangerous Liaisons (1988).
The film's release in territories such as UK was deliberately delayed to allow time to pass following the release of Dangerous Liaisons (1988). According to Christopher Hampton, the screenwriter of "Dangerous Liaisons," Milos Forman attended several performances of his play, "Les Liaisons Dangereuses," in London, and decided to film his own version of the Choderlos de Laclos novel. The competing production prompted Lorimar Films to rush "Dangerous Liaisons" into production, in order to beat "Valmont" into theaters. It worked, and "Dangerous Liaisons" was a critical and moderate box office success, while "Valmont" received mixed reviews and was a box office failure.
Fairuza Balk was 14 years old during production. She had a body double for scenes which contained nudity.
Wil Wheaton was originally chosen to play Danceny, but the producers of Star Trek: The Next Generation (1987) would not release him from his commitments, and the role went to Henry Thomas. (Ironically, Drew Barrymore, who played Thomas' little sister in E.T. the Extra-Terrestrial (1982) was nearly cast as Cecile de Volanges, Danceny's love interest, in the competing film, Dangerous Liaisons (1988).)
Milos Forman: [Schiavelli] Vincent Schiavelli, Forman's good-luck charm, appears as a servant named Jean.