Lake Austin is an ephemeral salt lake located in the Mid West region of Western Australia, approximately 21 km (13 mi) south of Cue and 55 km (34 mi) north of Mount Magnet.

Lake Austin is an evaporation basin for an arheic internal drainage system covering an area of 13,750 square kilometres (5,310 sq mi).

The lake usually fills in response to heavy rainfall in the summer and autumn; anecdotally, this occurs twice about every ten years.

Water salinity varies according to lake levels: recorded values have ranged from 44.8 mS/cm during a flooding event in 2000, to 164 mS/cm in the late 1970s.

The lake is situated on major ancient drainage lines and has massive supplies of saline water from sand aquifers at the base of the paleochannels from depths of 80 to 120 m (260 to 390 ft).