| Rustfontein Dam | |
| Name Official: | Rustfontein Dam |
| Dam Crosses: | Modder River |
| Res Name: | Rustfontein Dam Reservoir |
| Location: | Free State, South Africa |
| Operator: | Department of Water Affairs and Forestry |
| Dam Type: | gravity |
| Opening: | 1955 |
| Res Catchment: | 937 km2 |
| Coordinates: | -29.2708°N 26.6169°W |
Rustfontein Dam is a gravity type dam located on the Modder River near Thaba 'Nchu, Free State, South Africa. It was established in 1955 and serves mainly for domestic supply and industrial purposes. Its hazard potential has been ranked high (3).