The Shlina (Russian: Шлина) is a river in Firovsky, Bologovsky, and Vyshnevolotsky Districts, as well as of the closed urban-type settlement of Ozyorny of Tver Oblast of Russia.

It is a tributary of the Tsna River (technically, of the Vyshny Volochyok Reservoir) and belongs to the drainage basin of the Neva and the Baltic Sea.

The principal tributaries of the Shlina are the Granichnaya (right), the Shlinka (left), and the Lonnitsa (right).

The source of the river is Lake Shlino which is shared between Tver and Novgorod Oblasts.

The urban-type settlement of Firovo is located in the drainage basin of the Shlina.