Bergenhus fortress (Norwegian: Bergenhus festning) is a fortress located in Bergen, Norway. Located at the entrance of Bergen harbour, the castle is one of the oldest and best preserved stone fortifications in Norway.

The fortress contains buildings dating as far back as the 1240s, as well as later constructions built as recently as World War II. The extent of the enclosed area of today dates from the early 19th century. In medieval times, the area of the present-day Bergenhus Fortress was known as Holmen and contained the royal residence in Bergen, as well as a cathedral, several churches, the bishop’s residence, and a Dominican monastery.

Bergenhus is currently under the command of the Royal Norwegian Navy, which has about 150 military personnel stationed there. The fortifications Sverresborg fortress and Fredriksberg fortress also lie in the centre of Bergen. Haakon’s Hall and Rosenkrantz Tower are open for visits by the public. Koengen, the central part of Bergenhus Fortress is also known as a concert venue.