The Mologa is a river in Maksatikhinsky, Bezhetsky, Lesnoy, and Sandovsky Districts of Tver Oblast, Pestovsky District in Novgorod Oblast, and Ustyuzhensky and Cherepovetsky Districts in Vologda Oblast Russia. It is a left tributary of the Volga River. The lower course of the Mologa has been turned into the Rybinsk Reservoir. It is long, and the area of its basin . The principal tributaries of the Mologa are the Osen (right), the Volchina (left), the Kobozha (left), the Chagodoshcha (left) and the Sit (right, now it is a tributary of the Rybinsk Reservoir).

Mologa was a town in Yaroslavl Oblast, Russia, formerly situated at the confluence of Mologa and Volga Rivers, but now submerged under the waters of the Rybinsk Reservoir.