Floyd Mayweather Jr. vs. Conor McGregor, billed and promoted as The Money Fight, Boxing vs. MMA: Champion of Champions and The Biggest Fight in Combat Sports History, was a professional crossover boxing match between undefeated eleven-time five-division boxing world champion Floyd Mayweather Jr. and two-division mixed martial arts (MMA) world champion and, at the time, UFC World Lightweight Champion and Undisputed World Featherweight Champion Conor McGregor. The fight took place at T-Mobile Arena in Paradise, Nevada, on August 26, 2017, at the light middleweight limit (154 lbs; 69.9 kg). It was scheduled for twelve rounds and recorded the second highest pay-per-view buy rate in history, behind Mayweather vs. Pacquiao.

Mayweather extended his professional boxing undefeated streak to 50 victories and 0 defeats (50–0), surpassing the 49–0 record of Hall of Famer Rocky Marciano, after defeating McGregor by technical knockout (TKO) in the 10th round. Mayweather's guaranteed disclosed paycheck was $100 million and McGregor's guaranteed disclosed paycheck was $30 million. However, the purse for the two fighters was expected to be substantially higher for each, with Mayweather reportedly earning $280 million from the fight and McGregor earning $130 million.