The Osuga (Russian: река́ Осу́га) is a river in Selizharovsky, Kuvshinovsky, Torzhoksky, and Spirovsky districts of Tver Oblast of Russia, a right tributary of the Tvertsa. The Osuga is 167 kilometres long, and the area of its drainage basin is 2,410 square kilometres. The town of Kuvshinovo is along the banks of the Osuga.
