William Cotter

• William Richard Cotter, English soldier and recipient of the Victoria Cross
• William R. Cotter (politician), 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), Irish-born Roman Catholic bishop of Portsmouth, England
• Bill Cotter, Irish Fine Gael politician, former TD and Senator
• William Cotter (pirate), was a pirate who once owned the Gresham Estate in Edgewater, Maryland.