The Sperrlutter is a river in Lower Saxony, Germany, a roughly 12 km-long tributary of the Oder between Sankt Andreasberg and Bad Lauterberg in the Harz Mountains. The Sperrlutter rises at about 700 m in the vicinity of the Glückaufklippen. It flows initially south through the village of Silberhütte, where it is joined by the Wäschegrund. Then, it is joined by the Breitenbeek, the largest tributary of the Sperrlutter. Finally, the Sperrlutter reaches Bad Lauterberg and enters the Oder at a height of 309 m.