Bryophytes have been included in rather few studies of elevational gradients and studies on epiphytic bryophytes on different slopes of a single mountain have not been conducted in Indonesia. This research aims to compare species richness pattern, species composition, and zonation of epiphytic bryophytes on tree trunks on two different slopes of Mt Gede, West Java, Indonesia. We established an elevational transect on the North-North-East (Cibodas) and the South-South-West (Selabintana) slopes of the mountain. The transects ranged from 1500 to 2700 m each and sampling was carried out at 200 m intervals. The Cibodas slope is richer than the Selabintana slope, with 160 species (71 mosses and 89 liverworts) compared to 149 species (57 mosses and 92 liverworts), respectively. Species richness pattern on both slopes showed quadratic responses for mosses and cubic responses for liverworts. Pairwise elevation comparison between slopes showed that species composition is significantly different except for the highest plot (2700 m). Pairwise elevation comparison within the two transects revealed significant species composition changes at different elevations, indicating the presence of an elevational zonation of epiphytic bryophytes along the slopes. Based on overall bryophyte species composition, five elevational zones were recognized on each slope.