Gereb Segen is a reservoir located in the Hintalo Wajirat woreda of the Tigray Region in Ethiopia. The earthen dam that holds the reservoir was built in 2000 by SAERT.
In 2002, the life expectancy of the reservoir (the duration before it is filled with sediment) was estimated at 25 years.
The catchment of the reservoir is 3.53 km<sup>2</sup> large, with a perimeter of 11.66 km and a length of 5200 metres. The reservoir suffers from rapid siltation. The lithology of the catchment is Agula Shale. Part of the water that could be used for irrigation is lost through seepage; the positive side-effect is that this contributes to groundwater recharge.
There is a (much larger) dam with the same name, some 20 km to the northwest: Gereb Segen (May Gabat)