The Sernftal or Kleintal is an alpine valley within Glarus Süd, in the canton of Glarus, Switzerland. It is formed by the Sernf, a right tributary of the Linth. Situated in the Sernftal are the villages of Elm (977 m) and Engi (812 m). The Panix Pass at 2407 m connects the Sernftal with the anterior Rhine valley in Grisons.