The Kow Swamp, a freshwater lake and wetland, was formerly a swamp, that is now used for water storage. The lake is located in the Mallee region in north-central Victoria, Australia.

Kow Swamp lies in the Murray River valley, about 4.5 kilometres (2.8 mi) west of the town of Gunbower and 3 kilometres (1.9 mi) south of the town of Leitchville and also the Murray River, in the Shire of Campaspe. Its name comes from the Aboriginal word Ghow which refers to the white gypsum soil found at the swamp. It is a popular site for recreational fishing. Approximately 7 kilometres (4.3 mi) in length and 4 kilometres (2.5 mi) in width, the lake has a circumference of 15 kilometres (9.3 mi).

In the late 19th century Kow Swamp was managed by local irrigation trusts for off-river storage. In 1900 the capacity was increased to 51,730 megalitres (1.138×10 imp gal; 1.367×10 US gal).

Kow Swamp is an archaeological site which has produced human skeletal remains dating from the late Pleistocene, over 10,000 years ago.