Glarus Süd is a municipality in the Swiss canton of Glarus. It comprises the upper Linth valley, and the entire Sernf valley, and includes the villages of Betschwanden, Braunwald, Diesbach, Elm, Engi, Haslen, Hätzingen, Leuggelbach, Linthal, Luchsingen, Matt, Mitlödi, Nidfurn, Rüti, Schwanden, Schwändi and Sool. Glarus Süd is one of three municipalities of the canton of Glarus, the others being Glarus and Glarus Nord.