Sierre (German: Siders) is the capital of the district of Sierre in the canton of Valais in Switzerland. It has a population of 14,355.

It is situated on the French–German language border of the canton of Wallis (Valais in French). As a German-speaking minority lives in Sierre, it counts as one of the three official bilingual towns in Switzerland.

Sierre is first mentioned about 800 as Sidrium, though a 12th century document refers to the village being founded in 515. In 1179 it was mentioned as Sirro and in 1393 as Syder.

The area around the modern town, especially Gerunden hill, was settled very early. Archeological sites on Gerunden hill have produced neolithic objects and grave goods (including a polished stone ax), Bronze Age weapons and jewelry, Early Iron Age objects and Roman era inscriptions, jars, jewelry and coins. A soapstone pot from the Early Middle Ages and a gold signet ring with the name Graifarius from the 6th century have also been found. Other sites on nearby hills and near the chapel of Saint-Ginier, the Château de Villa, the churches of Sainte-Croix, Grands-Prés, Muraz, Glarey and Bernunes have yielded up graves originating from the Bronze Age to the Carolingian era. In Grands-Prés there is a fire pit from the beginning of the Late Iron Age (5th–6th century BC).