John Linwood Fox, or Tiger Jack Fox (b. April 2, 1907, d. April 6, 1954) as he was better known, was a colorful, hard punching, American light heavyweight boxer. Fox fought from 1928 to 1950.

Fox was defeated by Melio Bettina in his only crack at the light heavyweight championship, NYSAC version. In this elimination bout to name a champion, Fox was stopped in the 9th round. Two months before the fight he was stabbed near the heart in a Harlem hotel in a dispute over a woman.

Fox also fought and knocked out in two rounds former middleweight champion Bob Olin , and he knocked out Lou Brouillard in seven. He was kayoed in three rounds by future lightheavyweight champion John Henry Lewis.

Two of Fox's more surprising victories came against future heavyweight champion Jersey Joe Walcott. On May 12, 1937, Fox knocked out Walcott in the 8th round. In the following year Fox again defeated Walcott, this time by a ten round decision.

Fox is second on the all time list for first round knockouts, and was named to the Ring Magazine's list of 100 greatest punchers of all time.