Katie Taylor is an Irish professional boxer and former footballer. She is the undisputed and lineal world lightweight champion since 2019, and the undisputed and lineal world super lightweight champion since 2023.

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.