Gonzalo Pizarro y Alonso (; 1510 – April 10, 1548) was a Spanish conquistador and younger paternal half-brother of Francisco Pizarro, the conqueror of the Inca Empire. Bastard son of Captain Gonzalo Pizarro y Rodríguez de Aguilar (senior) (1446–1522) who as colonel of infantry served in the Italian campaigns under Gonzalo Fernández de Córdoba, and in Navarre, with some distinction, and María Alonso, from Trujillo. He was the half brother of Francisco and Hernándo Pizarro and the full brother of Juan Pizarro.