Lake Dey Dey is a salt lake in South Australia. It is one of many salt lakes in the eastern end of the Great Victoria Desert. It is normally dry, except during and after periods of heavy rainfall. It is part of the geological basin known as the Officer Basin. The larger Lake Maurice is to the south. Since 1985, Lake Dey Dey is part of the lands belonging to the Maralinga Tjarutja, a southern branch of the Pitjantjatjara. The community of Oak Valley is located nearby to the southwest.