Cecil Lewis "Jack" Thompson (August 17, 1904 – April 11, 1946) was an American boxer who twice held the World Welterweight Championship.
Born Cecil Thompson, his name was changed when he decided to become a professional fighter.
His father, who was training him, did not think "Cecil" was a fighter's name, so he chose "Jack." To avoid confusion with another fighter named "Jack Thompson," his father decided to use the ring name Young Jack Thompson.