The Caliciaceae are a family of mostly lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. Although the family has had its classification changed several times throughout its taxonomic history, the use of modern molecular phylogenetic methods have helped to establish its current placement in the order Caliciales. Caliciaceae contains 36 genera and about 600 species. The largest genus is Buellia, with around 300 species; there are more than a dozen genera that contain only a single species.