Diez or Díez is a surname. Notable people with the surname include:
Barbarito Diez (1909–1995), Cuban singerEduardo Díez de Medina, Bolivian politicianEmiliano Díez, Cuban actorFabio Díez, Argentinian-Spanish beach volleyball playerFederico Díez de Medina, Bolivian politicianFriedrich Christian Diez (1794–1876), German philologistFritz Diez, East German actor and theater director.Javier Diez Canseco (1948–2013), Peruvian politicianJuan Martín Díez (1775–1825), Spanish guerrilla leaderJuba Diez (born 1944), American politicianLuis Díez del Corral, Spanish lawyer and political scientistMauricio González-Gordon y Díez (1928–2013), Spanish sherry maker and conservationistNicolás Diez, Argentine footballerRicardo Gómez Diez, Argentine politicianSophie Diez (1820–1887), German operatic sopranoStefan Diez, (born 1971), German designerThomas Diez, Professor of International RelationsBlessed Victoria Díez Bustos de Molina (1903-1936), Spanish teacher and religious woman