The Bala Lake Railway is a preserved railway at Bala Lake, in Gwynedd, north Wales, which runs for a distance of 4+1⁄2 miles (7.2 km) using 2 ft (610 mm) gauge rolling stock. It was built on a section of the former Ruabon - Barmouth GWR route which was closed in 1965. This section runs along the south-eastern shore of Bala Lake. Another section of the former trackbed is today used by the Llangollen Railway.
The railway runs from Llanuwchllyn railway station, where the main railway buildings, workshops and offices are located, to Bala (Llyn Tegid) near Bala. The station at Bala is outside the town, and there have been various plans to extend the railway into Bala itself, but none have been realised. Steam locomotives on the line include Maid Marianworks number 822, Holy Warworks number 779, Aliceworks number 780 and George B works number 680, George B is currently undergoing a lengthy rebuild, all locos were built by the Hunslet Engine Company.