William Halsey (died after 1672) was a politician, soldier and judge in seventeenth-century Ireland. He was Mayor of Waterford, a member of each of the three Protectorate Parliaments, and the last Chief Justice of Munster. He sat in each of the three Protectorate Parliaments as member for the newly combined constituency of Waterford city and Clonmel. He was one of the "Kinglings" i.e. the party in Parliamentwhich unsuccessfully urged Oliver Cromwell to accept the English Crown in 1657.