Lake Wakatipu is an inland lake in the South Island of New Zealand. It is in the southwest corner of the Otago region, near its boundary with Southland. Lake Wakatipu comes from the original Māori name Whakatipu wai-māori.
With a length of 80 kilometres, it is New Zealand's longest lake, and, at 291 km², its third largest. The lake is also very deep, its floor being below sea level, with a maximum depth of 380 metres. It is at an altitude of 310 metres, towards the southern end of the Southern Alps. The general topography is a reversed "N" shape or "dog leg". The Dart River / Te Awa Whakatipu flows into the northern end, the lake then runs south for 30 kilometres before turning abruptly to the east. Twenty kilometres further along, it turns sharply to the south, reaching its southern end 30 kilometres further south, near Kingston.
The lake is drained by the Kawarau River, which flows out from the lake's only arm, the Frankton Arm, 8 km east of Queenstown. Until about 18,000 years ago the Mataura River drained Lake Wakatipu. The Kingston Flyer follows part of the former river bed now blocked by glacial moraine.