Guillaume de Ferrières (Latin: Guilelmus de Ferrariis, de Fornariis) (born in Provence, at a date unknown; died 7 September 1295 in Perpignan) was a Provençal French bureaucrat in the service of King Charles II of Naples, and a Roman Catholic Cardinal. Guillaume held the academic rank of Magister. He was Professor of Law at the University of Toulouse, ca. 1284. He was Provost of the Church of Marseille, 1289-1295, and papal Chaplain. He also held the titles of Consiliarius and Familiaris of King Charles.