Lake Paiku (or Peiku, Tibetan: Paiku-Tso or -Tsho) is a lake at elevation on the Tibetan Plateau at , south of the Yarlung Tsangpo (Brahmaputra) River. The lake is long and wide at its narrowest. It is surrounded by mountains reaching . Streams fed by glaciers cascade to the valley floor, but most sink into alluvial deposits before reaching the lake.