The Lakeside and Haverthwaite Railway is a heritage railway in Cumbria, England. The line runs from Haverthwaite via Newby Bridge to Lakeside at the southern end of Lake Windermere. Some services are timed to connect with sailings of steamers on Windermere, sailing up to Bowness and Ambleside.

The railway is a former branch line of the Furness Railway, and there is a train-boat connection that was established in 1868. The railway's locomotive fleet includes FR no. 20, Britain's oldest working standard gauge steam locomotive, which was built in 1863. The route of the connecting length from Haverthwaite to the junction at Ulverston was obliterated by road widening after British Railways closed it and before it was opened as a heritage railway.