Saturday Night Live aired its fifth season during the 1979–1980 television season on NBC, and also the final season with the original cast. This fifth season started on October 13, 1979 and ended on May 24, 1980. SNL's fifth season was released on DVD on December 1, 2009.

John Belushi and Dan Aykroyd left the show at the end of the fourth season, leaving a void in the cast that most fans thought would be the beginning of the end of the late-night sketch show.

To keep the show going, Lorne Michaels upgraded many of the show's writers to cast member status: Peter Aykroyd, Jim Downey, Brian Doyle-Murray, Don Novello, Tom Schiller and Alan Zweibel. Band leader Paul Shaffer also joined the cast, becoming the first person from the SNL band to become a cast member. Harry Shearer joined the show as a featured cast member and was promoted to repertory status during the season.

This would be the final season for everyone in the cast. Tom Davis and Downey would return to the show in future seasons as writers. Al Franken, Doyle-Murray, Novello, and Shearer would rejoin the cast in future seasons.