The Battle of the Transdanubian Hills (also known in Bulgaria as the Drava Operation (Bulgarian: Дравска операция, Dravska operatsiya)) was a defensive operation of the Bulgarian First Army during Bulgaria's participation in World War II against German Wehrmacht forces, who were trying to capture the north bank of the Drava river as part of Operation Spring Awakening. Combat in the Transdanubian Hills lasted from 6 to 21 March 1945. The German attacks failed to achieve their objectives and were then eclipsed by the large-scale Soviet offensive from the area of Lake Balaton to Vienna.