The Weser (German) or Vesdre (French) is a river in eastern Belgium, in the province of Liège, and is a right tributary to the river Ourthe. Its source lies in the High Fens (Hohes Venn, Hautes Fagnes), close to the border with Germany near Monschau. It flows through an artificial lake (), and then through the towns Eupen, Verviers, Pepinster and Chaudfontaine. The Vesdre flows into the Ourthe a few kilometers from Liège. Its total length is approximately .