Ostprignitz-Ruppin is a Kreis (district) in the northwestern part of Brandenburg, Germany. Area 2509 kmē, population 112,400 (2001). The district's capital is Neuruppin.
The district comprises the eastern part of the Prignitz region (the western part constituting the district of Prignitz) and an area called the Ruppiner Land.
Towns in the district include: Neuruppin, Rheinsberg[?], Fehrbellin[?], Kyritz[?], Neustadt (Dosse)[?], Wittstock[?].