Lake Murten (Lac de Morat, Murtensee) is a lake in the west of Switzerland. It is the smallest of the three lakes in the Jura region, with Lake Biel and Lake Neuchâtel being the other two.

The surface area of the lake is 22.8km². It is located in the cantons of Fribourg and Vaud. The main tributary is the river Broye. Water leaves the lake through the Broye Canal (Broyekanal) which leads into Lake Neuchâtel.

The lake - together with Lake Nauchâtel - is important to retain water from the river Aar in times of heavy rainfall in the Alps. This helps protecting densely populated areas, such as around the city of Bern. This can lead to the peculiar situation, that the water in the lake flows backwards.

Lake Murten is 8.2km long and up to 2.8km wide. Its maximal depth is 45m. The volume of the lake is approximately 0.55km³. The total catchment area is 693km². The water remains in the lake for an average 1.6 years.

On its southern shores is located the small town of Murten which gives the lake its name.