Lusen () is a mountain in Bavaria (Germany) and in the Plzeň Region of (Czech Republic) with a peak of 1373 metres. It is the sixth-highest mountain in the Bavarian Forest National Park/Bohemian Forest, behind the Großer Rachel, Kleiner Rachel, Kleiner Arber, Plattenhausenriegel and Großer Arber. Its peak is about south of the Czech Republic-Germany border. Streams forming on the north side become tributaries of the Vydra.