Juan Díaz (1480–1549), born in Seville, Spain, was a 16th century conquistador and the chaplain of the 1518 Grijalva expedition, the Itinerario (itinerary route) of which he wrote.
He was one of the first Spaniards who explored the named Isla de Sacrificios near Veracruz in Mexico, where the expedition found evidence of human sacrifice.