Beltrán de Cetina y del Castillo (Alcalá de Henares, 1521 - Mérida de Yucatán, 1600?) was one of the original conquistadors and founders of Mérida in the modern Mexican state of Yucatán. His siblings included: Renaissance poet Gutierre de Cetina; Ana Andrea del Castillo, self-described conquistadora and wife of Francisco de Montejo the Younger; and Gregorio de Cetina, also a conqueror of Yucatán.
His father, Beltrán de Cetina y Alcocer, was born to Gutierre de Cetina y Hurtado de Mendoza and Mencía de Alcocer (of partial converso ancestry) c. 1498. The parents came, for the most part, from old hidalgo families long resident in Alcalá de Henares, although the patrilineal descent ultimately stemmed from the village of Cetina, in the Kingdom of Aragon. As a youth Beltrán de Cetina y Alcocer moved to Seville, where he met and married Francisca del Castillo y Zanabria, daughter of García del Castillo and María Mayora, a local of likely Morisco descent. The nuptials were celebrated in 1518 in Seville. In 1519 was born Gutierre, in 1521 Beltrán in Alcalá de Henares, in 1525 Ana Andrea, and in 1527 Gregorio.
The family lived for many years in the parish neighborhood of Santa María la Blanca, within the old aljama or Jewish quarter of Seville. The father, possibly owing to family influences, obtained in 1536 the job of almoxarife mayor (chief tax official and treasurer) for the city and its ports. The Cetina family's comfortable position allowed them to own slaves (some of them Indian) and to realize the construction of a family tomb in the Dominican convent of Madre de Dios de la Piedad, in which would also be laid the remains of doña Juana de Zúñiga and doña Catalina Cortés, wife and daughter of Hernán Cortés, respectively; as well as the great-granddaughters of Christopher Colombus.