|Location||Mantasoa, Analamanga Region|
|Purpose||Power, water supply|
|Dam and spillways|
|Type of dam||Buttress|
|Height||20 m (66 ft)|
|Length||122 m (400 ft)|
|Total capacity||125,000,000 m3 (101,000 acre·ft)|
|Surface area||20 km2 (7.7 sq mi)|
Mantasoa Dam is a buttress dam on the Varahina-North River, a tributary of the Ikopa River, near Mantasoa in the Analamanga Region of Madagascar. The dam was constructed by the French Business Company between 1937 and 1938. It creates Lake Mantasoa which has a surface area of 20 km2 (7.7 sq mi). The dam itself is made of 8,000 m3 (10,000 cu yd) of concrete and has a reinforced buttress design. Water released from the dam supplies a regulated flow to hydroelectric power station at the Antelomita Dams downstream. A saddle dam on the north side of the Mantosoa reservoir regulates water flow into the Mandraka River for the Mandraka Dam downstream.
- Tsiazompaniry Dam – on the Varahina South River
- "The French civil engineering works in the world dams 1860-2012" (PDF). IESF. Retrieved 17 March 2014.
- "Mantasoa and lake". Mantasoa. Retrieved 17 March 2014.
- "Dams of Madagascar". UN FAO. Retrieved 17 March 2014.