The Arroyito Dam (in Spanish, Embalse de Arroyito) is the fifth of five dams on the Limay River in northwestern Argentine Patagonia (the Comahue region), approximately at , 315 m above mean sea level. It was inaugurated in 1979.
The dam is made of compacted loose materials. It has a volume of 4 million m³, measuring 37 m in height and 3,500 m in length. It is used primarily for the generation of hydroelectricity, with an installed power of 120 MW. It generates on average 560 GWh per year. It also serves as a check dam for El Chocón, located upstream.
The reservoir has an area of 38.6 km² and a volume of 300 million m³. Its depth is 7.7 m on average (maximum: 15 m).