Monsters, Inc is a 2001 American computer-animated film and the fourth feature-length film produced by Pixar Animation Studios. It was directed by Pete Docter, co-directed by Lee Unkrich and David Silverman, and written by Jill Culton, Peter Docter, Ralph Eggleston, Dan Gerson, Jeff Pidgeon, Rhett Reese, Jonathan Roberts, and Andrew Stanton. The starring voices are John Goodman and Billy Crystal as Sulley and Mike, two monsters who work at a power plant that powers the monster world with children's screams, Mary Gibbs as Boo, a little girl who enters the monster world, Steve Buscemi as Randall, a rival monster, and James Coburn as Mr Waternoose, the plant's owner.

The film was released to theatres by Walt Disney Pictures in the United States on November 2, 2001, in Australia on December 26, 2001, and in the United Kingdom on February 8, 2002. It was a commercial and critical success, grossing over $525,366,597 worldwide. Review aggregator Rotten Tomatoes also reported extremely positive reviews with a 95% approval rating.