Kung Kasalanan Man (English: If It's A Sin) is a 1989 Philippine thriller melodrama film directed by Eddie Garcia from a screenplay by Amado Lacuesta Jr. and Raquel Villavicencio, based on a komiks serial of the same name written by Gilda Olvidado. It revolves around two Irmas: one is the real Irma who has owned properties and the other is Jo, the fake Irma, who is the former's high school friend who stole the former's identity by having plastic surgery after her former lover beat her and destroyed her face.

Produced and released by Viva Films, the film stars Dina Bonnevie, Timmy Cruz, Tonton Gutierrez, and Julio Diaz, with the film's theme song "Kung Kasalanan Man" performed by Rey Valera, cinematography by Joe Batac Jr. and its musical score was composed by Jaime Fabregas. The film was theatrically released on 21 June 1989, to a critical and box office success.