| Modderpoort Dam | |
| Name Official: | Modderpoort Dam |
| Dam Crosses: | Rietfontein River |
| Res Name: | Modderpoort Dam Reservoir |
| Location: | Northern Cape, South Africa |
| Operator: | Department of Water Affairs and Forestry |
| Dam Type: | buttress & earth-fill |
| Opening: | 1953 |
| Coordinates: | -31.9472°N 22.1336°W |
Modderpoort Dam is a combined buttress & earth-fill type dam located on the Rietfontein River, near Beaufort West, Northern Cape, South Africa. It was established in 1953 and serves primarily for irrigation purposes. The hazard potential of the dam has been ranked significant (2).