The year 2013 was the 21st year in the history of the Ultimate Fighting Championship (UFC), a mixed martial arts promotion based in the United States. 2013 started with UFC on FX: Belfort vs. Bisping. 2013 also saw the introduction of the women's bantamweight weight class with UFC 157: Rousey vs. Carmouche.

Vítor Vieira Belfort is a Brazilian professional boxer and retired mixed martial artist who competed for the Ultimate Fighting Championship (UFC), where he fought in the Heavyweight, Light Heavyweight and Middleweight divisions. He is the UFC 12 Heavyweight Tournament Champion, as well as the former UFC Light Heavyweight Champion and Cage Rage World Light Heavyweight Champion. Known for his explosive knockout power, Belfort is tied for fifth for the most finishes in UFC history with 14. Belfort also competed for MMA promotions Pride FC, Strikeforce, Affliction, and Cage Rage.