William Fisk (17 July 1871 – 18 December 1940) was an Australian politician who represented the South Australian House of Assembly seat of Glenelg from 1938 to 1940 as an independent. Fisk was born in Adelaide, and studied at Whinham College, the South Australian School of Mines and the University of Adelaide. He undertook an apprenticeship in pharmacy and dentistry in 1885 before becoming manager of a chemist in Jetty Road, Glenelg, subsequently taking over the business himself. He was mayor of the Corporate Town of Glenelg from 1931 to 1938, at the time the longest-serving mayor in Glenelg's history. He was a prominent advocate for the construction of the Anzac Highway. Fisk also served on the executive of the Pharmacy Board of South Australia, the council of the Pharmaceutical Society,