This is a list of Ultimate Fighting Championship (UFC) champions in each weight division.

At the time of the UFC's inception in 1993, the sport of mixed martial arts was unsanctioned in the United States, and it did not include weight classes. Instead of the traditional championship model, tournaments were held with the winner receiving a permanent appellation. In response to criticism from Senator John McCain that saw the loss of its television deal and the banning of the sport in thirty-six states, the UFC increased its cooperation with state athletic commissions and introduced weight classes in 1997.

The original codification for weight classes introduced only two divisions: heavyweight, which grouped competitors above 200 pounds (91 kg), and lightweight, which encompassed all other competitors. The UFC would later rename its lightweight division to middleweight and add lightweight 170 pounds (77 kg) and bantamweight 155 pounds (70 kg) divisions. In 2000, the New Jersey State Athletic Control Board completely took over regulation in its home state, and its rules and weight classes became the de facto rule set for mixed martial arts. The UFC realigned their weight classes to comply with the new regulations in 2001.

Frank James Edgar (born October 16, 1981) is an American mixed martial artist, who competes as a lightweight in the Ultimate Fighting Championship and is a former UFC Lightweight Champion. His first career loss came against Gray Maynard in 2008, which marked the beginning of a noted rivalry. He later avenged the loss to Maynard with a KO victory in 2011. As of March 2012, he is ranked as the #2 lightweight in the world by Sherdog.com.

Born and raised in Toms River, New Jersey, Frankie Edgar wrestled at Toms River High School East, making it to the New Jersey state championship tournament on three occasions, placing second as a junior and fifth as a senior. Edgar is the oldest of 3 children, Edgar went on to compete in the NHSCA Senior Nationals and placed second before he finished high school. He continued wrestling at Clarion University of Pennsylvania, where he qualified for the nationals all four years there. Edgar is also an assistant coach for the Rutgers University wrestling team.

Edgar entered his first mixed martial arts fight with only a few weeks of training outside of his wrestling background. Edgar originally trained with Rob Guarino of Rhino Fight Team, but today he is part of the Gracie system under Ricardo Almeida in Hamilton, NJ. Since seventh grade Edgar has wrestled with Steve Rivera at Elite Wrestling NJ in Jackson, NJ. His boxing trainer is Mark Henry of Millstone, NJ.

Benson Henderson (born November 16, 1983) is an American mixed martial artist. He is currently fighting for the Ultimate Fighting Championship and is the current UFC Lightweight Champion. Henderson is known for his aggressive style and his ability to escape from deep submission attempts. As of March 2012, Henderson is ranked as the #1 lightweight fighter in the world by Sherdog.

Henderson was born in Colorado Springs, Colorado to a Korean American mother and an African American father. He was raised in Federal Way, Washington. He attended Decatur High School from 1998 to 2001. Ben became a part of the high school's wrestling team. After graduating from high school, he attended Dana College in Blair, Nebraska and graduated in 2006 with a double major in criminal justice and sociology. While attending Dana College, Henderson was on the wrestling team, and was twice named an NAIA All-American. Henderson is a proud Christian, and uses his fighting to share his beliefs. He is known to quote scripture after bouts, and walks into each fight to a gospel song.

Joseph Christopher Stevenson (born June 15, 1982) is an American mixed martial artist fighting out of Hesperia, California. Competing as a welterweight, he won The Ultimate Fighter 2 welterweight tournament. Stevenson fought most of his UFC career as a lightweight, and made his featherweight debut at UFC Live: Kongo vs. Barry. Stevenson is noted for his effective use of the guillotine choke. 'Daddy' holds notable wins over Melvin Guillard, Yves Edwards, Nate Diaz, Spencer Fisher, Gleison Tibau, and Kurt Pellegrino. He holds an 8-8 record in the promotion.

Stevenson's father died from bone marrow cancer. Stevenson and his first wife, Lisa, have two sons, Joe Jr. and Tyler.

Stevenson and his second wife Maia have two sons, Frankie and Maximus.

He graduated in the class of 2000 from Silverado High School in Victorville, California.

Stevenson began wrestling at the age of 11 and started Jiu Jitsu at the age of 13. He moved to Las Vegas in 2004, and began training at Marc Laimon's Cobra Kai in Las Vegas. In March 2008, Stevenson opened his own school in his hometown of Victorville, California. "Joe Stevenson's Cobra Kai" teaches MMA as well as boxing, kickboxing, wrestling and Jiu Jitsu. On November 8, 2008, Stevenson earned his Brazilian Jiu-Jitsu black belt under Robert Drysdale. After his loss to Diego Sanchez, Stevenson got a call from Rashad Evans for an invite to check out his camp at Jackson's Submission Fighting. After being reluctant at first, he finally joined Greg Jackson's camp in April 2009.

Anthony Pettis (born January 27, 1987) is an American mixed martial artist who competes in the lightweight division and is currently signed with the Ultimate Fighting Championship. A professional MMA competitor since 2007, Pettis has made a name for himself mainly fighting in his home state of Wisconsin. He is a former fighter for the World Extreme Cagefighting (WEC), where he was the last WEC Lightweight Champion before merging the promotion into the UFC.

Born to Eugene Pettis Jr. and Annette Garcia, Anthony Pettis grew up in the south side of Milwaukee, Wisconsin along with his older brother Ray Pettis and younger brother Sergio "Lil' Showtime" Pettis. Pettis is of Mexican and Puerto Rican ancestry, his grandfather Anglicized the family name from Perez to Pettis, to avoid discrimination. Pettis attended Dominican High School.

Anthony "Showtime" Pettis made his professional MMA debut in December 2007. He compiled an undefeated record of 8-0 in shows all based in Milwaukee, Wisconsin before debuting with the WEC. Pettis also has a professional kickboxing background.