William FitzGeoffrey de Mandeville, 3rd Earl of Essex

William fitz Geoffrey de Mandeville (died 1227) was the third Earl of Essex of the second creation from 1216 to his death. He was the second son of Geoffrey Fitz Peter and Beatrice de Say and he succeeded his elder brother Geoffrey FitzGeoffrey as earl and inheritor of the Mandeville barony. He was married to Christina Fitzwalter, one of Robert Fitzwalter's daughters, but died without heirs and the earldom became extinct.