Introduction The proposed research is part of ongoing operations research within World Vision's Access: Infant and Maternal Health Programme. This study aims to identify key context features and underlying mechanisms through which community health committees build community capacity within the field of maternal and child health. This may help to improve programme implementation by providing contextually informed and explanatory findings for how community health committees work, what works best and for whom do they work for best for. Though frequently used within health programmes, little research is carried out on such committees’ contribution to capacity building—a frequent goal or proposed outcome of these groups.

Methods and analysis The scarce information that does exist often fails to explain ‘how, why, and for whom’ these committees work best. Since such groups typically operate within or as components of complex health interventions, they require a systems thinking approach and design, and thus so too does their evaluation. Using a mixed methods realist evaluation with intraprogramme case studies, this protocol details a proposed study on community health committees in rural Tanzania and Uganda to better understand underlying mechanisms through which these groups work (or do not) to build community capacity for maternal and child health. This research protocol follows the realist evaluation methodology of eliciting initial programme theories, to inform the field study design, which are detailed within. Thus far, the methodology of a realist evaluation has been well suited to the study of community health committees within these contexts. Implications for its use within these contexts are discussed within.

Ethics and dissemination Institutional Review Boards and the appropriate research clearance bodies within Ireland, Uganda and Tanzania have approved this study. Planned dissemination activities include via academic and programme channels, as well as feedback to the communities in which this work occurs.