Gonzalo Pizarro y Alonso was a Spanish conquistador. He was the younger paternal half brother of Francisco Pizarro, who led the Spanish conquest of the Inca Empire. Pizarro was the illegitimate son of Gonzalo Pizarro y Rodríguez de Aguilar (1446–1522), who, as an infantry colonel, served under Gonzalo Fernández de Córdoba during the Italian Wars. He was also the younger paternal half brother of Hernándo Pizarro y de Vargas and the older paternal full brother of Juan Pizarro y Alonso.

Conquistadors or conquistadores was a term used to refer to Spanish and Portuguese colonialists of the early modern period. During the Age of Discovery, conquistadors sailed beyond the Iberian Peninsula to the Americas, Oceania, Africa and Asia, establishing new colonies and trade routes. They brought much of the "New World" under the dominion of Spain and Portugal.