A phytochemical study of the methanol extract of the Antarctic lichen Stereocaulon caespitosum Redgr. led to the isolation of a tridepside (1), two depsides (2 and 3), a montagnetol derivative (4), and four mono-phenolic compounds (5–8). The structures of these compounds were confirmed by 1D- and 2D-nuclear magnetic resonance (NMR) experiments, as well as by comparison with published values. This is the first phytochemical study of S. caespitosum. In particular, compounds 1, 3, 4, and 8 have been isolated for the first time from the genus Stereocaulon and the family Stereocaulaceae. The chemotaxonomic significance of the isolated compounds is discussed. Keywords: Stereocaulon caespitosum; Antarctic lichen; Depside; Montagnetol.