Moosburg (Slovene: Možberk) is a market town in the Klagenfurt-Land district in the Austrian state of Carinthia, northwest of its capital Klagenfurt. It consists of the Katastralgemeinden Bärndorf, Gradenegg, Kreggab, Moosburg (Možberk), St. Peter, Seigbichl (Žihpolje), Tigring (Tigrče) and Tuderschitz (Tudrešiče).
Located within an area, which had at least been settled since Roman times, Moosburg is the site of the Arnulfsfeste Kaiserpfalz, first mentioned in a 879 deed. Arnulf of Carinthia, the Carolingian king of East Francia and Holy Roman Emperor, grew up here and used the castle as a residence. Subsequent an estate of the Counts of Gorzia and the House of Habsburg, it was replaced by nearby Moosburg Castle and decayed during the 16th century.
Moosburg is situated along the B 95 Turracher Straße federal highway. The A 2 Süd Autobahn can be reached via the Krumpendorf and Pörtschach junctions.
Moosburg is twinned with: