The Teloschistales are an order of mostly lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. According to one 2008 estimate, the order contains 5 families, 66 genera, and 1954 species. The predominant photobiont partners for the Teloschistales are green algae from the genera Trebouxia and Asterochloris.

The higher-level phylogenetic relationships of the Teloschistales and other members of the two major subclasses of Lecanoromycetes, Lecanoromycetidae and Ostropomycetidae, were clarified in a 2018 publication by Kraichak and colleagues. In the Teloschistales, the family Teloschistaceae has a sister taxon relationship with Megalosporaceae, and the clade containing these two families is itself sister to a clade containing families Brigantiaeaceae and Letrouitiaceae.

Species of Teloschistales occur in both maritime and inland settings, and their local diversity can be strongly structured by habitat. On the Commander Islands (Russian Far East), an inventory combining plot-based collecting with molecular identifications recorded 36 species across coastal, tundra and floodplain habitats, with the highest richness in coastal sites and generally poorer plots in tundra. In the same study, arctic-alpine circumpolar taxa predominated in tundra plots, while floodplains supported mainly corticolous and lignicolous species and included circumboreal and amphi-Pacific elements. The archipelago's Teloschistales funga also included taxa otherwise associated with maritime north-east Asia and the western coast of North America alongside more widely distributed boreal and circumpolar species; the authors suggested that island chains such as the Aleutian Islands can act as stepping stones for dispersal between the two continents, and they reported several taxa that may be restricted to the Commander Islands.