Year One is a 2009 American adventure comedy film directed by Harold Ramis and distributed by Columbia Pictures. The film was written by Harold Ramis, Gene Stupnitsky, and Lee Eisenberg and stars Jack Black and Michael Cera. A parody on the book of Genesis, the plot follows two cavemen who travel to the city of Sodom 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 Judd Apatow's production company The Apatow Company and was released on June 19, 2009. It grossed $19.6 million in its opening weekend and $62.4 million worldwide, against a budget of $60 million. Upon release, it was panned by critics and audiences, receiving only a 14% approval rating based on 173 votes on Rotten Tomatoes. This marked the last film to be directed, produced, written by and starring Harold Ramis before he died in February 2014.