| Mazegawa Dam | |
| Name Official: | 馬瀬川第二ダム |
| Dam Crosses: | Maze River |
| Location: | Gero, Gifu Prefecture, Japan. |
| Dam Length: | 263.0 meters |
| Dam Height: | 44.5 meters |
| Construction Began: | 1966 |
| Opening: | 1976 |
| Res Capacity Total: | 9,736,000 m3 |
| Res Catchment: | 1,049.0 km2 |
| Res Surface: | 70 hectares |
| Coordinates: | 35.7314°N 137.1403°W |
| Plant Capacity: | 28.8 MW |
is a dam in the city of Gero in Gifu Prefecture, Japan on the Maze River, part of the Kiso River system. The dam is a concrete gravity dam with a height of 44.5 meters. It was constructed for hydroelectric power generation and its associated power plant has a capacity of 288,000 kilowatts of power. It is managed by the Chubu Electric Power Company.