Domingo Betanzos (d. at Valladolid, September 1549) was a Spanish Dominican missionary to Central America.
A native of León in Spain, he first studied jurisprudence at Salamanca, then became a Benedictine and lived as a hermit on the Island of Ponza for five years. He then joined the Dominicans, who had established themselves on Hispaniola (Santo Domingo) in 1510. Betanzos went there four years later.
In 1516 he, with several other Dominicans, wrote a letter to Las Casas on the rapid disappearance of the Indians of the Antilles, concerning the numbers of the aboriginal population, and the excesses thought to have been committed by the Spaniards. In 1526, Betanzos went to Mexico and founded the Dominican province of Santiago de México.
Tomás de Berlanga almost immediately claimed that it belonged to his newly founded province of Santa Cruz with the provincial seat at Santo Domingo. Betanzos went to Spain in 1531 and obtained from the Holy See the independence of his foundation. He also established the Dominican Province of Guatemala.
As Provincial of Mexico in 1535, he organized missions among three Indigenous groups stocks: the Nahua people, the Mixtec people, and the Zapotec people. He returned to Spain in 1549, and died in September of the same year at Valladolid. The Bishopric of Guatemala was tendered to Betanzos, but he declined it.
In his letter of 1516, he acquiesced in the views of his brethren of the order on the question of Indian policy. In the "Opinion" (Parecer) given by him in 1541, and approximately repeated in 1542, just as the "New Laws" regarding the Indies were to be promulgated under the influence of Las Casas, he took an entirely different attitude. He quietly gave his opinion in a sense diametrically opposed to the measures Las Casas pressed upon the Government.
Betanzos was an intimate friend of distinguished Franciscans of Mexico – Archbishop of Mexico Juan de Zumarraga, Toribio Benavente "Motolinia", and others, who did not harmonize with Las Casas. He is credited with the authorship of an addition to the "Doctrina" of Fray Pedro de Córdoba which appeared in 1544, and possibly in 1550, but this is not established.