Ås is a municipality in Akershus county, Norway. It is part of the Follo traditional region. The administrative centre of the municipality is the village of Ås. The parish of Aas was established as a municipality on 1 January 1838. Ås is one of the fastest-growing municipalities in Akershus, with a population of 20,652 in 2020, and an increase of 539 in 2008.