The Grande Dixence Dam (French pronunciation: [gʁãd diksãs]) is a concrete gravity dam on the Dixence at the head of the Val d'Hérémence in the canton of Valais in Switzerland. At 285 m (935 ft) high, it is the tallest gravity dam in the world, seventh tallest dam overall, and the tallest dam in Europe. It is part of the Cleuson-Dixence Complex. With the primary purpose of hydroelectric power generation, the dam fuels four power stations, totaling the installed capacity to 2,069 MW, generating approximately 2,000 GWh annually, enough to power 400,000 Swiss households.

The dam withholds the Lac des Dix ('Lake of the Ten'), its reservoir. With a surface area of 4 km², it is the second largest lake in Valais and the largest lake above 2,000 m in the Alps. The reservoir receives its water from four different pumping stations; the Z’Mutt, Stafel, Ferpècle and Arolla. At peak capacity, it contains approximately 400,000,000 m³ (1.4×10¹⁰ cu ft) of water, with depths reaching up to 284 m (932 ft). Construction on the dam began in 1950 and was completed in 1961, before officially commissioning in 1965.