| Três Irmãos Dam | |
| Name Official: | Barragem Três Irmãos |
| Location Map: | Brazil |
| Coordinates: | -20.6656°N -51.3014°W |
| Country: | Brazil |
| Location: | Pereira Barreto, São Paulo |
| Purpose: | Power, navigation |
| Status: | O |
| Dam Type: | Embankment with gravity sections |
| Dam Crosses: | Tietê River |
| Dam Length: | 3640m (11,940feet) |
| Dam Height: | 82m (269feet) |
| Res Name: | Três Irmãos Reservoir |
| Res Capacity Total: | 13373000000m2 |
| Res Capacity Active: | 3450000000m2 |
| Res Capacity Inactive: | 9923000000m2 |
| Res Catchment: | 699000km2 |
| Res Surface: | 785km2 |
| Res Elevation: | 328m (1,076feet) |
| Plant Operator: | Companhia Energética de São Paulo (CESP) |
| Plant Commission: | 1993-1999 |
| Plant Type: | Conventional |
| Plant Turbines: | 5 x 161.5MW Francis-type |
| Plant Capacity: | 807.5MW |
The Três Irmãos Dam is an embankment dam with gravity sections on the Tietê River in Pereira Barreto of São Paulo state in Brazil. The dam is about upstream of the river's confluence with the Paraná River. It supports the largest hydroelectric power station on the river with an installed capacity of . The dam was completed in 1991 and the five Francis turbine-generators were commissioned between November 1993 and January 1999. It is owned and operated by Companhia Energética de São Paulo (CESP). The dam also provides for navigation with two ship locks.[1] [2]