Drepanolejeunea robinsonii C.E.Zartman & A.M.Sierra is described and illustrated herein as a new species from the Amazon basin. The type collections are from lowland rainforest habitat in the central Amazon of Brazil. Morphological characters which distinguish the new species from the phenotypically similar Drepanolejeunea polyrhiza (Nees) Grolle & R.L.Zhu, are: 1) ovate leaf form; 2) conspicuously acute leaf apices; and 3) irregularly dentate to serrate teeth composed of 2–5 cells on leaf margins. Androecia were repeatedly observed on separate gametophytes suggesting the new taxon is dioecious, however neither gynoecia nor perianths have yet to be observed.