A new species of Lejeuneaceae from montane cloud forest of Colombia and Costa Rica, Harpalejeunea scabra, is described and illustrated. The new species is characterized by the papillose dorsal leaf surface, a feature occurring in several related genera such as Lejeunea and Drepanolejeunea, but new to Harpalejeunea. Further diagnostic characters of H. scabra include the dorsal leaf margin with 1-3 teeth and the peculiar lobule with twinned apical teeth, free margin bordered by very narrow cells and aperture circular with the distal end of the apical margin adnate to the surface of the lobe. The new species somewhat resembles the enigmatic Drepanolejeunea navicularis Steph. from páramo of Colombia and Venezuela. The affinities of the two species are discussed.