Training Day is a 2001 American crime thriller film directed by Antoine Fuqua and written by David Ayer. It stars Denzel Washington as Alonzo Harris and Ethan Hawke as Jake Hoyt, two LAPD narcotics officers followed over a 24-hour period in the gang-ridden neighborhoods of Westlake, Echo Park, and South Central Los Angeles. It also features Scott Glenn, Eva Mendes, Cliff Curtis, Dr. Dre, Snoop Dogg, and Macy Gray in supporting roles.

Training Day was released on October 5, 2001, by Warner Bros. Pictures. It received generally positive reviews from critics, who praised Washington and Hawke's performances but were divided on the screenplay. The film received numerous accolades and nominations with Washington's performance earning him the Academy Award for Best Actor and Hawke being nominated for Best Supporting Actor at the 74th Academy Awards.

A television series based on the film, produced by Jerry Bruckheimer, was announced in August 2015 and premiered on February 2, 2017, on CBS. Only Noel Gugliemi, Tom Berenger and Raymond J. Barry reprised their roles. The show was cancelled after one season.