Burgruine Ortenburg is a mediæval castle near Baldramsdorf in Carinthia, Austria. It was erected in the late 11th century by ministeriales of the Bavarian Prince-Bishops of Freising, who then held large possessions in the Duchy of Carinthia. Their descendants began to call themselves Counts of Ortenburg. The castle is located on the northern slope of the Gailtal Alps overlooking the Drava valley.
Damaged by the 1348 Friuli earthquake, the significance of the castle diminuished after the extinction of the Ortenburgs in 1418. The estates were inherited by Count Hermann II of Celje and in 1456 finally seized by the Imperial House of Habsburg. In 1524 the comital title passed to Gabriel von Salamanca, who had his new residence, Porcia castle built in the nearby town of Spittal an der Drau.