Lake Wakatipu is an inland lake on the South Island of New Zealand. The lake (located at ) is in the southwest corner of Otago, near the border with Southland.

With a length of 80 kilometres, it is the South Island's longest lake. At 291 km², Lake Wakatipu is the third largest lake in New Zealand. It lies at an altitude of 310 metres, towards the southern end of the Southern Alps. The general topography of the lake is a reversed "N" shape. The Dart River flows into the northern end of the lake, which then runs south for 30 kilometres before turning abruptly to the east. Twenty kilometres further along the lake, it again turns sharply to the south, reaching its southern end 30 kiletres further south near the town of Kingston.

The lake is drained by the Kawarau River which flows from the lake near Queenstown, which lies on the northern shore of the lake, close to eastern end of its middle section. It is a very deep lake, its floor being up to 100 metres below sea level, and "breathes", its waters rising and falling regularly by some 20 centimetres for reasons not as yet fully understood.

Wakatipu is renowned for its scenic beauty, with The Remarkables mountain range lying along its southeastern edge, although a recent boom in population and tourism around Queenstown threatens to kill this golden goose. The lake is a popular venue for adventure tourism, with skifields, paragliding, bungy jumping and tramping tracks within easy reach of the lake, and a vintage steamboat, the T.S.S. Earnslaw regularly plies its waters. Several vineyards are also found close to the lake.