The Tarwin River is a perennial river of the West Gippsland catchment, located in the South Gippsland region of the Australian state of Victoria. The Tarwin River is the primary river system within South Gippsland Shire and has a catchment area of approximately 1,500 square kilometres (580 sq mi), predominantly rural with small pockets of residential land use. It flows south from the Strzlecki Ranges and discharges in the eastern reaches of Anderson Inlet, a shallow estuary connected to Bass Strait.