The Naab (Czech: Nába) is a river in Bavaria, Germany, and is a left tributary of the Danube. Including its main source river Waldnaab, it is 196.6 km (122 mi) long.The Naab is formed by the confluence of the Waldnaab and the Haidenaab in Luhe-Wildenau, south of Weiden in der Oberpfalz. It flows generally south, through the towns Nabburg, Schwandorf and Burglengenfeld.