The Upper Sûre Lake (Luxembourgish: Stauséi Uewersauer, French: Lac de la Haute-Sûre, German: Obersauer-Stausee) is a large reservoir in north-western Luxembourg. It is the largest body of water in the country. It gives its name to the commune of Lac de la Haute-Sûre, which was formed in 1979.

It was created by the Esch-sur-Sûre Dam which was built in the 1950s to meet Luxembourg's drinking water and electricity needs. The town of Esch-sur-Sûre/Esch-Sauer nestles at one end of the lake. Immediately above it, the river has been dammed to form a hydroelectric reservoir extending some 10 kilometres (6.2 mi) up the valley. Its average surface area is 3.8 km (1.5 sq mi), or about 0.15% of Luxembourg's total area.

The region around the reservoir forms the Upper Sûre Natural Park, a Luxembourgish national park. The valley of the Upper Sûre surrounding the reservoir has been designated as a Ramsar site, in Luxembourg and in neighboring Belgium, since 2004.

Surrounded by luxuriant vegetation and peaceful creeks, the lake is a center for water sports, such as sailing, canoeing, and kayaking. Such outdoor activities, which make it an attractive spot for tourists, has led to the growth of a local crafts industry. The lake has a very high level of water quality.

• Upper Sûre Natural Park

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