Pier Luigi de Borgia, 1st duke of Gandía (Spanish: Pedro Luis de Borja, Latin: Petrus Ludovicus de Boria) (1458 or 1460–1488 or 1491) was a Valencian noble. Pier Luigi was the son of Cardinal Rodrigo Borgia (later Pope Alexander VI), and half-brother of Cesare Borgia, Gioffre Borgia, Giovanni Borgia and Lucrezia Borgia.
He was married to María Enríquez de Luna of the House of Enríquez. Due to Pier Luigi's untimely death, she would later wed his younger brother Giovanni (also known as Juan) in September 1493.
Pier Luigi Borgia fought alongside the Spanish armies during the Granada War (Reconquista). Following his heroic triumph during the Battle of Ronda, King Ferdinand II rewarded him with the title of 'grandee of Spain' on 18 May 1485.
The lands of Gandia, the ancestral home of the Borgia family, were initially inherited by Pier Luigi (Pedro Luis). However, before becoming duke of Gandía, he purchased the duchy through a financial agreement with local nobles Andrés de Cabrera, Marquis of Moya, and his wife, Beatriz de Bobadilla. Through this agreement, Pier Luigi was required to provide the marquis an unknown sum, albeit considered small, and accept certain rights pertaining to the crown and of Valencia over the lands of the duchy. Some sources state that Pedro Luis' father gave him 50,000 ducats in order to purchase the territory. In late 1485, King Ferdinand II officially elevated Pier Liugi's status to duke of Gandía.