Less than Zero is a 1987 American drama film directed by Marek Kanievska, loosely based on the 1985 novel by Bret Easton Ellis. The film stars Andrew McCarthy as Clay, a college freshman returning home for Christmas to spend time with his ex-girlfriend Blair (Jami Gertz) and his friend Julian (Robert Downey Jr.), both of whom have become drug addicts. The film explores the culture of wealthy, decadent youth in Los Angeles.

Less than Zero received mixed reviews among critics. Ellis hated the film initially, but his view of it later softened. He insists that the film bears no resemblance to his novel and feels that it was miscast apart from Downey and James Spader.

Clay Easton is a strait-laced college freshman on the East Coast of the United States, who returns home to Los Angeles for Christmas to find things very different from the way he left them. His high school girlfriend and now model, Blair, has become addicted to cocaine and has been having sex with Clay's high school best friend, Julian Wells. Julian, whose life has gone downhill after his startup record company fell apart, has also become a drug addict. As a result, he has been cut off by his family for stealing to support his habit and reduced to homelessness. Julian is also being hassled by his dealer, a former classmate named Rip, for a debt of $50,000 that he owes to him.

Clay's relationship with Blair rekindles and Julian's behavior becomes more volatile. His addiction is worsening and since he does not have the money to pay off his debt, Rip forces him to become a prostitute to work it off. After suffering through a night of overdose and hiding from Rip, Julian decides to quit and begs his father to help him. The next day, Julian tells Rip his plans for sobriety, which Rip does not accept. Rip soon lures Julian to a Christmas party for affluent gay men in Palm Springs. Clay finds Julian and rescues him; after a violent confrontation with Rip and his henchman, Clay, Julian, and Blair all escape and begin the long drive through the desert so Julian can attempt to achieve sobriety once and for all. However, the damage has already been done; the next morning Julian dies from heart failure in the car.

After Julian's funeral, Clay and Blair sit on a cemetery bench and reminisce about their friend. Clay then tells Blair that he is returning to the East Coast and wants her to go with him. She agrees to his offer.

Lastly, a snapshot of the three of them at graduation is seen, the last time they were happy together.

Ellis's book was originally optioned by producer Marvin Worth for $7,500 before its publication in June 1985 with the understanding that 20th Century Fox would finance it.

The purchase was sponsored by Scott Rudin and Larry Mark, vice presidents of production. The book became a best seller but the producers had to create a coherent story and change Clay, the central character, because they felt that he was too passive. They also eliminated his bisexuality and casual drug use. Worth hired Pulitzer Prize-winning playwright Michael Cristofer to write the screenplay. He stuck close to the tone of the novel and had Clay take some drugs but did not make him bisexual. The studio felt that Cristofer's script was too harsh for a commercial film.