Alien Nation is a 1988 American science fiction action film written by Rockne S. O'Bannon and directed by Graham Baker. The ensemble cast features James Caan, Mandy Patinkin, and Terence Stamp. Its initial popularity inaugurated the beginning of the Alien Nation media franchise. The film depicts the assimilation of the "Newcomers", an alien race settling in Los Angeles, much to the initial dismay of the local population. The plot integrates the neo-noir and buddy cop film genres with a science fiction theme, centering on the relationship between a veteran police investigator (Caan) and an extraterrestrial (Patinkin), the first Newcomer detective. The duo probe a criminal underworld while attempting to solve a homicide. Alien Nation explores murder, discrimination and science fiction.

The film was a co-production between American Entertainment Partners and 20th Century Fox, which distributed it theatrically. Alien Nation was released in the United States on October 7, 1988, and grossed over $32 million worldwide, becoming a moderate financial success. The film was met with mixed critical reviews before its theatrical release, although it has since gained a cult following. The motion picture spawned a short-lived television series, five television films, a set of comic books, and a number of novels, all in an attempt to continue the character development surrounding its fictional alien culture.