Donna Sancha of Aragon (1478 in Gaeta – 1506 in Naples), or Sancia of Aragon, was an illegitimate daughter of King Alfonso II of Naples and his mistress Trogia Gazzela. In 1494, she was married to Gioffre Borgia, the son of Pope Alexander VI. Upon her marriage she and her new husband were created Prince and Princess of Squillace, a province in the south of Italy. Allegedly, Sancha had affairs with both Cesare and Giovanni, and her affair with Giovanni is sometimes said to be the reason for Cesare's alleged murder of Giovanni in 1497. Her brother Alfonso of Aragon married the Pope's daughter, and her husband's sister, Lucrezia Borgia. Her life among the Borgias became a turbulent one after Cesare made an advantageous marriage with a French princess, Charlotte d'Albret, in order to secure French support for his military campaigns. This put his interests in direct conflict with those of the Italian states, Sancha's home of Naples being no exception, which had long been nervous of militant French interests.
Her brother Alfonso was brutally murdered in 1500 by Cesare, jealous of his influence over Lucrezia. Sancha herself, now a political embarrassment, was imprisoned in the Castel San Angelo in Rome until the death of Pope Alexander in 1503. Upon his death, she managed to regain her freedom and returned to Naples with her young nephew, Rodrigo, whom she raised as her own. She never lived with her husband, Gioffre, again. Interestingly, Cesare visited her not long after and asked if she would take on the care of Giovanni "The Roman Infant", which she agreed to do. She died of an undisclosed illness in 1506, a year before Cesare.