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 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 two coaches, along with the finalists of the tournament, fought at The Ultimate Finale, a televised MMA fight card that aired live at the completion of the series.

The series premiered on April 5, 2007 on Spike TV in the United States and Canada at 10:00 p.m. ET/PT and concluded on June 23. Filming began in mid-January 2007.