William Gwynn (1856 - 1 April 1897) was a Welsh international rugby union forward who played club rugby for Swansea and would later become secretary of the Welsh Rugby Union. Gwynn was an all-round sportsman and as well as his success on the rugby pitch he also player cricket for , of which he became vice-president, and Glamorgan. Gwynn had also played association football and had captained Battersea College XI through two undefeated seasons. He would later become a referee and would officiate the very first football game between Swansea Town and Cardiff City.