William Barrett (died 1584) was English consul at Aleppo.
He was there when John Eldred and his companion, William Shales, arrived there on 11 June 1584; he died eight days after their arrival, as is recorded in Eldred's narrative.
He wrote a treatise on The Money and Measures of Babylon, Balsara, and the Indies, with the Customes, &c., which occupies pp.
406 to 416 of the second volume of Richard Hakluyt's Collection of Voyages, folio edition, 1810.
A paragraph records the discovery of the island of Saint Helena, and its use as a provision depôt for the 'Portugale' traders with India.