The Aghstafachay reservoir (Azerbaijani: Ağstafaçay su anbarı) is a large reservoir in the Aghstafa District of northwestern Azerbaijan.

[1] The Aghstafachay reservoir was built on Aghstafa River in 1969 near the village of Cəfərli of Qazakh District.

[2][3] The area of the Aghstafa reservoir is 6.3 km2 (2.4 sq mi).

The height of the hydroelectric power station built on the reservoir is 52 m (171 ft).

The reservoir provides irrigation water to 135 ha (330 acres) of land in Aghstafa, Qazakh, Shamkir and Tovuz raions.