Year One is a 2009 American adventure comedy film directed by Harold Ramis, produced by Ramis, Judd Apatow, and Clayton Townsend, written by Ramis, Gene Stupnitsky, and Lee Eisenberg, and stars Jack Black, Michael Cera, Oliver Platt, David Cross, Christopher Mintz-Plasse, Vinnie Jones, Juno Temple, June Diane Raphael, Olivia Wilde, Bill Hader, and Hank Azaria. A parody on the book of Genesis, the plot follows two cavemen who travel to the city of Sodom to save their love interests after being banished from their tribe. Problems quickly emerge during their journey, as they encounter several biblical figures along the way.

The film was produced by Apatow's production company The Apatow Company and was released on June 19, 2009 by Columbia Pictures. It grossed $19.6 million in its opening weekend and $62.4 million worldwide, against a budget of $60 million. Upon release, Year One was panned by critics and audiences, receiving only a 14% approval rating based on 173 votes on Rotten Tomatoes. This was the last film to involve Ramis before his death in 2014.