Daniel Jeffery Henderson (born August 24, 1970) is an American former mixed martial artist and Olympic wrestler, who last competed as a middleweight in the Ultimate Fighting Championship. He was the last Strikeforce Light Heavyweight Champion and was the last Welterweight (80 kg (176.4 lb)) and Middleweight (95 kg (209.4 lb)) champion of Pride Fighting Championships. Additionally, Henderson was the Brazil Open '97 Tournament Champion, the UFC 17 Middleweight Tournament Champion, the Rings: King of Kings 1999 Tournament Champion and the Pride Weltwerweight Grand Prix Tournament Champion. During his career, Henderson also challenged for the UFC Middleweight Championship (2x), the UFC Light Heavyweight Championship and the Strikeforce Middleweight Championship. He was the first mixed martial artist to concurrently hold two titles in two different weight classes in a major MMA promotion. At the time of his retirement after UFC 204, he was the oldest fighter on the UFC roster. Known to be one of the greatest mixed martial artists of all time having defeated a total of seventeen MMA world champions across four major MMA promotions (UFC, PRIDE FC, Strikeforce, and RINGS).

Henderson grew up on a ranch in Apple Valley, California. He started wrestling at a young age and started being noticed as a relentless competitor. When he entered high school he placed on the wrestling team with his brother Tom at Victor Valley High, which was coached by Sam Gollmyer and assisted by their father Bill Henderson and Joe Barrios.[citation needed] He is of Native American, English, Scottish and French descent. Henderson had previously been prescribed testosterone replacement therapy (TRT) after being diagnosed with low testosterone levels in 2007. However, TRT has no longer been allowed in UFC competition since 2014. After TRT was banned, Henderson said that he quit using TRT "cold turkey".

Henderson was coached by Bob Anderson, of the defunct California Jets. He placed second at the California State Wrestling Championship in 1987 and Victor Valley won the team title. In 1988, he placed fifth in the state finals and several months later won national crowns in both freestyle and Greco Roman at the Junior Nationals in Cedar Falls, Iowa.[citation needed]

According to the March 2007 Confederated Umatilla Journal: "Henderson's grandmother, Alice (Bergevin) LeJune, is an enrolled member of the Confederated Tribes and owns land on the Umatilla Indian Reservation. From all accounts, Henderson is 1/16 Walla Walla Native American." In the interview Henderson commented: "Now I know I'm Walla Walla. It's refreshing to find some of those things out. I look Indian and I knew I had some, but I didn't know what tribe or exactly how much. It will be good to be able to tell my kids about their heritage.