BackgroundPoor quality of health services and socio-cultural dynamics may severely limit utilization of health services. Facility health committees were established in several states in northern Nigeria to reduce these barriers. The committees were charged with mobilizing communities, improving quality of health services, and promoting utilization of maternal and child health services. This study assessed this intervention.MethodsTo obtain a comprehensive picture of facility health committees’ influence on maternal and child health services, we selected 33 facilities in three states in northern Nigeria (Jigawa, Kaduna, Kano) where the intervention was active. For each of these facilities we interviewed committee members (n = 399), conducted focus group discussions with a subset of committee members (18 focus groups), interviewed facility health providers (two providers from each facility), and conducted client exit interviews (n = 501).ResultsFacility health committees appear to have a positive influence on quality of maternal and child health services in the selected facilities. Committee members, health providers, and facility clients all agree that the committees have a tangible positive effect. The most important roles of the committees are to mobilize the community and increase demand for maternal and child health services, in a region where demand is very low. Committee activities further improve health services in many ways, including advocacy, community-facility coordination, fund raising, money donation, and problem mitigation.ConclusionFacility health committees can be invaluable in contributing to improved demand for and access to quality maternal and child health services in health facilities in northern Nigeria. They provide strong linkages between community members and the health facilities, directly work to increase demand for services, and address supply-side challenges that often limit utilization of services in health facilities. The intervention can be improved by more broadly communicating committee activities in the community, and by incentivizing facility health committee members.Electronic supplementary materialThe online version of this article (10.1186/s12913-018-2902-7) contains supplementary material, which is available to authorized users.