Lake Pelku[1] (Tibetan: དཔལ་ཁུད་མཚོ, Wylie: dpal khud mtsho, THL: pel khü tso),[2] Pelkhu,[3] or Paiku (Chinese: 佩枯错; pinyin: pèigǔ cuò)[a] is a lake at 4,591 meters (15,062 ft) elevation on the Tibetan Plateau in Shigatse Prefecture.

Streams fed by glaciers cascade to the valley floor, but most sink into alluvial deposits before reaching the lake.

The surrounding catchment is an endorheic basin with no outlet.

It would overflow into the Yarlung Tsangpo with a water level about 100 meters (330 ft) higher.

The lake's brackish water is evidence that it has not overflowed in hundreds, if not thousands, of years.