The Vièze is a river in Switzerland, in the canton of Valais, a tributary of the Rhône. It flows at the bottom of the Illiez valley to join the Rhône at the commune of Monthey. It takes its source above Champéry, towards Berthe, the Berroi ridge and the Col de Cou (west-southwest of Champéry), north of the Portes du Soleil for the Vièze de Morgins.