Saturday Night Live aired its twenty-ninth season during the 2003–04 television season on NBC. The twenty-ninth season began on October 4, 2003 and ended on May 15, 2004 with 20 episodes in all.

Before the start of the season Chris Kattan and Tracy Morgan left the show and Dean Edwards was fired. Despite Kattan and Morgan's departure, the two would make guest appearances in several episodes throughout the season.

Before the season started, Will Forte, Seth Meyers and Jeff Richards were all promoted to repertory status, while Fred Armisen remained a featured player.

The show added two new black cast members: stand-up comedian Finesse Mitchell and Kenan Thompson, a former child star from the Nickelodeon comedy shows All That and Kenan and Kel. With this season, Thompson becomes the first SNL cast member to be born after the show's premiere in 1975 and the first SNL cast member to get his start on children's shows.

This season saw the first appearance of Justin Timberlake as an SNL host.