Arzúa is a municipality in the province of A Coruña, in the autonomous community of Galicia, in northwestern Spain. It covers an area of 155.89 km² and has a population of 5,887, giving a population density of 37.76 people per km².
The municipality is one of the Galician municipalities with the most cows per capita, a characteristic tied to the region's longstanding dairy farming tradition.