Rat River may refer to:
Canada Rat River (Burntwood River tributary), Manitoba Rat River (Red River of the North tributary), Manitoba Rivière au Rat (Weedon), a tributary of the Saint-François River in Quebec, Canada Rivière aux Rats, a tributary of the Saguenay River in Quebec, Canada
Romania Rât (disambiguation), several rivers
Elsewhere River Rat, a tributary of the River Gipping, England Rat River, Wisconsin, the former name of Silver Cliff, Wisconsin, US