/ˈlɛvən/ LEV-ən) is a short river in the ceremonial county of Cumbria, falling within the historic boundaries of Lancashire.

It drains Windermere from its southernmost point and flows for approximately 8 miles (13 km) into the northern reaches of Morecambe Bay.

The Leven is navigable upstream as far as Low Wood, and downstream from Windermere to Newby Bridge.

The river is popular with kayakers due to the continuous grade III+ rapids found between Newby Bridge and Haverthwaite and a relatively stable water level sustained by Windermere.

In 1903 a train crossing the railway bridge over the river was derailed by high winds during the Ulysses Storm.