William Morris "Billy" Hughes, CH,KC (25 September 1862 –28 October 1952), Australian politician, was the seventh Prime Minister of Australia, from 1915 to 1923.

Over the course of his 51-year federal parliamentary career (and an additional seven years prior to that in a colonial parliament), Hughes changed parties five times: from Labor (1894–1916) to National Labor (1916–17) to Nationalist (1917–30) to Australian (1930–31) to United Australia (1931–44) to Liberal (1944–52). He was expelled from three parties, and represented four different electorates in two states.