Gyalidea pacifica Harada & Vezda is described as new from Hachijo Island of the Izu Islands, Japan. It was found growing on non-calcareous stones. The lichen genus Gyalidea in the family Solorinellaceae is characterized by its crustose thallus; coccoid green phycobiont; brownish apothecia; non-amyloid hymenium; almost simple and septate paraphyses; and hyaline, muriform (or transversely septate) spores. Gyalidea is represented worldwide by 26 previously described species, occurring on foliicolous, saxicolous, terricolous, and corticolous substrates (Etayo & V~zda 1994; Kalb & Hafellner 1992; VWzda & Poelt 1991). Hitherto, only G. japonica Harada & V~zda (1991), which was found on non-calcareous pebbles in Shizuoka-ken, has been recorded from Japan. Recently, however, the senior author discovered a second species, occurring on non-calcareous stones, among specimens collected on Hachijo Island of the Izu Islands, about 300 km south of Tokyo. It is newly described here as Gyalidea pacifica Harada & Vrzda sp. nov.