José Ángel Nápoles was a Cuban-born Mexican professional boxer. He was a two-time undisputed welterweight champion, having held the WBA, WBC, and The Ring welterweight titles between 1969 and 1975. He is frequently ranked as one of the greatest fighters of all time in that division and is a member of the International Boxing Hall of Fame. His record of the most wins in unified championship bouts in boxing history, shared with Muhammad Ali, was unbeaten for 40 years. After debuting professionally in Cuba, he fought out of Mexico and became a Mexican citizen.

In boxing, the undisputed champion of a weight class is the boxer who simultaneously holds world titles from all recognized major organisations by each other and the International Boxing Hall of Fame. There are currently four major sanctioning bodies: WBA, WBC, IBF and WBO. There were many undisputed champions before the number of major sanctioning bodies recognizing each other increased to four in 2007, but there have only been 19 boxers to hold all four titles simultaneously.