The Gileppe Dam (French Barrage de la Gileppe) is an arch-gravity dam on the Gileppe river in Jalhay, Liège province, Wallonia, Belgium. It was built in the 1870s to supply water for the wool industry in nearby Verviers. The monumental structure with its unusually thick profile played an important role in establishing an international standard for masonry gravity dams as a technology for major water supply systems. It was considered one of the strongest dams in Europe at the time, and it was the first dam built in modern Belgium. In the first decade of the 21st century, it was noted as supplying most of the drinking water for Verviers, as well as industrial water, and as producing hydroelectricity.