Bayandur is a river in the Zangazur uezd of the former Yelizavetpol (Ganja) governorate, later in the former Gorus district, and currently in the Syunik province. It is located 5 km to the northwest of the village of Bayandur. Its length is 14 km.

The hydronym was coined in association with the name of the Old Turkic tribe “Bayandur”.