The Terek (Те́рек) is a major river in the Northern Caucasus, flowing through Georgia and Russia into the Caspian Sea. It rises in Georgia on the slopes of Mount Kazbek, then flows north through North Ossetia and the city of Vladikavkaz. It turns east to flow through Chechnya and Dagestan before dividing into two branches which empty into the Caspian Sea. Below the city of Kizlyar it forms a swampy river delta around 60 miles (100 km) wide.

The river is a key natural asset in the region, being used for irrigation and hydroelectric power in its upper reaches.

The main cities on the Terek are Vladikavkaz, Mozdok and Kizlyar.