Peter of Castile, in Spanish Pedro de Castilla, was an infante of Castile, a younger son of King Sancho IV and his wife María de Molina. He held the lordships (señoríos) of Cameros, Almazán, Berlanga, Monteagudo and Cifuentes and was the majordomo of his brother, King Ferdinand IV of Castile. During the minority of his nephew Alfonso XI, he shared the regency of Castile with his mother and uncle, John el de Tarifa, between 1313 and his death.