Lake Greenly (dual name: Puwanna) is a body of water in Australia.

Lake Greenly is in the locality of Coulta on the Lower Eyre Peninsula in the state of South Australia, and 1,300 kilometres (810 mi) west of the Australian capital city, Canberra.

Lake Greenly is a natural lake that covers a surface area of 22 square kilometres (8.5 sq mi), has an average depth of 4 metres (13 ft).

Lake Greenly boasts a total water volume of 0.09 cubic kilometres (73,000 acre⋅ft), and has a total shore line of 22 kilometres (14 mi).

The lake, which sits at an elevation of 30 metres (98 ft), drains a watershed that covers 399 square kilometres (154 sq mi).