The canton of Glarus (German: Kanton Glarus [ˈɡlaːrʊs] ; Romansh: Chantun Glaruna; French: Canton de Glaris; Italian: Canton Glarona) is a canton in east-central Switzerland. The capital is Glarus. The population speaks a variety of Alemannic German. The majority of the population (81%) identifies as Christian, about evenly split between Protestants and Catholics.

According to legend, the inhabitants of the Linth Valley were converted to Christianity in the 6th century by the Irish monk Saint Fridolin, the founder of Säckingen Abbey in what is now the German state of Baden-Württemberg. From the 9th century, the area around Glarus was owned by Säckingen Abbey, the town of Glarus being recorded as Clarona.