John William Radcliffe (16 August 1917 – 28 January 1984), more commonly known as Bill Radcliffe, or also Illiam y Radlagh, was a Manx language activist, author, and teacher who was involved with the revival of the Manx language on the Isle of Man in the 20th century. His work recording the last native speakers of the language with the Irish Folklore Commission helped to ensure that a spoken record of the Manx language survived.