Aarwangen is a municipality in the Aarwangen (district), in the Canton of Bern, in Switzerland.
Aarwangen grew from from a fortified toll crossing over the River Aare, in a region where there were few realistic crossing places.
In 1432, after the conquest of the neighbouring Aargau, Schloss Aarwangen was purchased by the city of Bern, which then acquired the remainder of the former Grünenberg estate, including the area of the current district of Aarwangen, in 1480.