Joe Frazier vs. Muhammad Ali, billed as the Fight of the Century was a boxing match between WBC/WBA heavyweight champion Joe Frazier (26–0, 23 KOs) and The Ring/lineal heavyweight champion Muhammad Ali (31–0, 25 KOs), held on Monday, March 8, 1971, at Madison Square Garden in New York City.

The fight is widely regarded as the biggest boxing match in history and arguably the single most anticipated and hyped sporting event ever. It was the first time ever that two undefeated boxers fought each other for the heavyweight title.

The bout held broad appeal for many Americans, including non-boxing and non-sport fans. Ali, who had been stripped of his titles by boxing authorities for refusing to submit to the draft for the Vietnam war, had become a symbol of the left-wing anti-establishment movement during his government-imposed exile from the ring,^[7] while Frazier had been adopted by the conservative, pro-war movement.

Frazier won in 15 rounds via unanimous decision. It was the first of a trilogy, followed by the rematch fights Super Fight II (1974) and Thrilla in Manila (1975), both won by Ali.