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.