Atla tibelliorum is a rare species of saxicolous (rock-dwelling) in the family Verrucariaceae.

Found in Finland and the United States, it was formally described as a new species in 2016 by Juha Pykälä and Leena Myllys.

The type specimen was collected by the first author near Toskaljärvi lake (Porojärvi [fi], Enontekiö); there, in a calcareous alpine grassland at an altitude of 730 m (2,400 ft), the lichen was found growing on dolomite pebbles.

It has also been collected from Franklin Bluffs, Alaska, where it was growing on high-pH soil in dwarf shrub tundra.

The species epithet tibelliorum honours "Sanja and Leif Tibell, the mother and father of the genus Atla".