The Ultimate Fighter 5 was the fifth season of the Ultimate Fighting Championship produced reality television series The Ultimate Fighter. As with the show's usual format, sixteen prospective mixed martial arts fighters were secluded in a house near Las Vegas, Nevada and trained together while participating in a single-elimination tournament, with the winner being awarded a six-figure UFC contract. This season featured only one weight class, lightweights (146–155 lb) and the fighters were divided into two teams; one coached by former UFC Lightweight Champion Jens Pulver and the other by former UFC Welterweight Champion and former lightweight champion B.J. Penn. The season was well-known among fans for the large number of fighters kicked off of the show.

The Ultimate Fighter is an American reality television series and mixed martial arts (MMA) competition produced by the Ultimate Fighting Championship (UFC) and Pilgrim Media Group currently airing on ESPN+. It previously aired for fourteen seasons on Spike TV. The show features professional MMA fighters living together in Las Vegas, Nevada, and follows them as they train and compete against each other for a prized six-figure contract with the UFC. The series debuted on January 17, 2004, with its first episode, "The Quest Begins". To date, there have been thirty one seasons of the show, two per calendar year, some years having only one season. Each season features either one or two weight classes in the tournament.