Significant disparities in reproductive, maternal, newborn, and child health (RMNCH) outcomes and intervention coverage exist between the Mountains and other ecoregions of Nepal. Delivery of essential health services to remote mountainous areas is challenging and access is a known barrier to utilization. However, the contribution of demand-side barriers is poorly understood. Consequently, policies and programs cannot strategically target constraints to increase coverage. This systematic review identifies demand-side barriers to utilization of RMNCH services in the Mountain districts of Nepal. Research was drawn from MEDLINE, Web of Science, Scopus, Google Scholar, Eldis, and unpublished literature. Beyond inaccessibility, utilization is undermined by costs of care-seeking, traditional attitudes and practices, low status of women, limited health knowledge, dissatisfaction with service quality, and low and inequitable care by community health workers. The intensity and repercussions of these barriers are of greater magnitude in the Mountains where delayed care-seeking combines with long distances for critical health consequences.