Aarwangen is a village and a municipality in the Oberaargau administrative district in the Canton of Bern in Switzerland .

Aarwangen is first mentioned in 1255 as villa Arwangen.

Aarwangen grew from a fortified toll crossing over the river Aare , in a region where there were few realistic crossing places. The first bridge was built in the early years of the 13th century, and by the 16th century this had developed into a covered wooden bridge and customs post, defended by a castle.

During the 18th century, by road, and the 19th century, by rail, this became a busy and important trade route for the movement of goods between the western and eastern parts of Switzerland.

The municipal coat of arms is black and silver.