Jack Clowes (31 July 1866 – 10 March 1927), was an American-born British rugby union footballer of the 1880s, who played in Yorkshire for Halifax, and was selected to play at a representative level for the British Isles on the 1888 British Lions tour to New Zealand and Australia, the first tour by a team representing the British Isles.
Clowes is notable for having been prohibited from playing on that 1888 tour due to the Rugby Football Union deeming him a professional, and for the subsequent ramifications of his case contributing to the creation of the Northern Rugby Football Union in 1895.