Alfonso I of Asturias (c. 693 ??757) , called the Catholic, was the third King of Asturias, reigning from 739 to his death in 757. His reign saw an extension of the Christian domain of Asturias, reconquering Galicia and Le籀n.

He succeeded his brother-in-law Favila, and was succeeded by his son, Fruela I. Alfonso's youngest son, Mauregatus, also became king, and his daughter Adosinda was consort to King Silo of Asturias. The dynasty started by Alfonso was known in contemporary Al-Andalus as the Astur-Leonese dynasty.