Audunborg (Auduns borg) was a castle and fortification built by Norwegian nobleman Audun Hugleiksson on his inherited estate near the village of Ålhus on the shores of the Jølstravatn in the municipality of Jølster in Vestland county, Norway.

Recent research claims that Audun himself spent little time in his castle as his activities kept him either in Bergen, in the east of the country or abroad.

As a baron, Audun Hugleiksson was allowed to keep a hird (armed retinue) a right otherwise reserved for the king.

[3] [4] Today, only the ruins remain of the castle that stood at the tip of Hegreneset by Jølstravatn in Sunnfjord.

A memorial at Audunborg, carved by Jørgen P. Solheimsnes from Jølster, was erected on the site of the former castle in 1960.