The Infante Luís, 5th Duke of Beja (pron. lu'iʃ; Louis or Lewis) (Abrantes, March 3,1506 — Marvila, in Lisbon, November 27, 1555) was the second son of King Manuel I of Portugal and his second wife Maria of Aragon, princess of Spain (Catholic Kings' third daughter), and therefore a Portuguese infante.
Luís succeeded his father as the 5th Duke of Beja and was also made 9th Constable of the Kingdom (Portuguese: Condestável do Reino) and Prior of the Order of Saint John of Jerusalem, with its Portuguese headquarters in the town of Crato.
He did not marry but had a natural son of Yolande (Violante) Gomes, a Pelicana (the she-pellican), a Jewess, who is said to have died a Nun in Almoster, Santarém, on 16 July 1568, daughter of Pedro Gomes, from Évora. Some say they eventually married perhaps at Évora, thus legitimating their issue for every purpose). Their son António, Prior of Crato, would be one of the claimants to the throne after the disaster of Alcácer Quibir and subsequent death of King Sebastian of Portugal and the dynastic crisis that followed, and, according to some historians, the 18th King of Portugal during the year of 1580.