Cladonia mitis is a species of fruticose lichen in the family Cladoniaceae. It was formally described as a new species in 1918 by German lichenologist Heinrich Sandstede. It has previously been classified in genus Cladina before molecular phylogenetic studies showed this to be a part of Cladonia. Cladonia mitis is morphologically quite similar to Cladonia arbuscula, and some authors have considered it to be a variety or subspecies of the latter. They differ mainly in the production of secondary compounds: Cladonia mitis produces chemicals in the rangiformic acid complex, which C. arbuscula does not.