Leon Spinks (July 11, 1953 – February 5, 2021) was an American professional boxer who competed from 1977 to 1995. In only his eighth professional fight, he won the undisputed heavyweight championship in 1978 after defeating Muhammad Ali in a split decision, in what is considered one of the biggest upsets in heavyweight boxing history. Spinks was later stripped of the WBC title for facing Ali in an unapproved rematch seven months later, which he lost by a unanimous decision.
Besides being heavyweight champion and his characteristic gap-toothed grin (due to losing two and later all four of his front teeth), Spinks gained notoriety for the disaster which befell his career following his loss to Ali. However, he did challenge once more for the WBC heavyweight title in 1981 (losing to Larry Holmes by TKO in the third round), and the WBA cruiserweight title in 1986 (losing to Dwight Muhammad Qawi by TKO in the sixth round).
As an amateur, Spinks won numerous medals in the light heavyweight division.