Bazzania amadoi is a new species described and illustrated here based on material collected during a study of the bryophyte flora in the Brazilian Amazon Mountains, Monte Roraima National Park, Roraima State, Brazil. Bazzania is the largest genus of Lepidoziaceae, with ca. 30 species recognized in South America. A combination of leaves slightly bifid and recurved to the ventral side, underleaves imbricate and connate with the leaves on only one side, and vittae absent with only a region of larger leaf cells in the mid-lower portion of the leaves (vitta-like), distinguishes B. amadoi from the similar B. gracilis. The new taxon is placed within the key for the identification of species from the Brazilian Amazon domain, and represents an addition to the rich endemic flora of the Brazilian Amazon mountains of the Guiana Highlands. A detailed illustration of the new species is included, and also its informal conservation assessment.