William Cotter may refer to:
William Richard Cotter (1882–1916), English soldier and recipient of the Victoria Cross William R. Cotter (politician) (1926–1981), Democratic Party member of the United States House of Representatives from Connecticut William R. Cotter (college president), lawyer and President of Colby College William Cotter (bishop) (1866–1940), Irish-born Roman Catholic bishop of Portsmouth, England Bill Cotter (born 1943), Irish Fine Gael politician, former TD and Senator William Cotter (pirate) (1670–1702), was a pirate who once owned the Gresham Estate in Edgewater, Maryland.
See also William Cotter Maybury, politician from Michigan