Aarwangen Castle, Medieval castle in Aarwangen, Switzerland.

Aarwangen Castle is a medieval fortress positioned along the Aar River, marked by sturdy stone walls and a central tower offering views over the landscape. The building displays typical defensive design, combining administrative and residential spaces within its structure.

The lords of Aarwangen, ministerials of the Kyburgs, built the castle in the 13th century to guard the Aare crossing; the line died out with Johann von Aarwangen in 1350. Bern bought castle and lordship from Wilhelm von Grünenberg in 1432, making it the seat of a Landvogtei where 75 Landvögte resided until 1798. In 1805 Bern repurchased the castle, which then served as chancery, court and prison until the court moved to Burgdorf in 2012.

The castle's name comes from the lords of Aarwangen, a Kyburg ministerial family who held it until Johann von Aarwangen died in 1350. Bernese bailiffs then resided here, 75 in all, until 1798. Since 2020 the Schloss Aarwangen foundation has run the building, aiming to make it a meeting place for the Oberaargau region.

The castle stands on the south bank of the Aare, right by the Aarwangen bridge on the road from Niederbipp to Langenthal. The site was empty from 2012, when the district court moved to Burgdorf, until the Schloss Aarwangen foundation took it over in 2020. The foundation now works to keep the complex open to the public.

The castle stood empty after the district court moved to Burgdorf in 2012. In 2019 the Grand Council accepted a motion by 143 votes to zero to give the building to a foundation, which was founded inside the castle on 3 November 2020.