Bare-knuckle boxing (or simply bare-knuckle) is a full-contact combat sport based on punching without any form of padding on the hands.

The difference between street fighting and a bare-knuckle boxing match is that the latter has an accepted set of rules, such as not striking a downed opponent. The rules that provided the foundation for bare-knuckle boxing for much of the 18th and 19th centuries were the London Prize Ring Rules.

By the late 19th century, professional boxing moved from bare-knuckle to using boxing gloves. The last major world heavyweight championship happened in 1889 and was held by John L. Sullivan. The American National Police Gazette magazine was recognized as sanctioning the world championship titles.

Bare-knuckle boxing has seen a resurgence in the 21st century with the English promotion BKB (Bare Knuckle Boxing) along with other UK promotions such as Warrington’s UBKB (Ultimate Bare Knuckle Boxing) and Bare Fist Boxing Association (BFBA) & American promotion Bare Knuckle Fighting Championship (BKFC) and BYB Extreme (BYB) based out of Miami Florida.

In September 2022 it was announced that Bare Knuckle Fighting Championship had acquired the UK organisation Bare Fist Boxing Association (BFBA) to form Bare Knuckle Fighting Championship UK (BKFC UK). The move meant that BKFC would now regularly hold shows throughout the United Kingdom.