Vegadeo is a municipality in the Autonomous Community of the Principality of Asturias, in northern Spain. It lies in the western part of the region, near the boundary with Galicia.
The municipality is bordered to the north and east by Castropol, to the south by Villanueva de Oscos, Taramundi, and San Tirso de Abres, and to the west by the Eo River and San Tirso. The Eo River forms part of its western edge.