William John "Bill" Mumm OBE JP (26 March 1922 – 11 December 1993) was a New Zealand rugby union player. A prop, Mumm represented Buller at a provincial level. He was a member of the New Zealand national side, the All Blacks, in 1949, playing one test match against Australia.

He later served as chairman of the Buller County Council and was appointed an Officer of the Order of the British Empire in the 1990 Queen's Birthday Honours, for services to local government