Community governance, the direct (co-)management of public services by community members, is a popular approach to improve the quality of, and access to, healthcare services–including in so-called ‘fragile’ states. The effectiveness of such approach is, however, debated, and scholars and practitioners have emphasised the need to properly reflect on the contextual features that may influence social accountability interventions. We study a randomised intervention during which community-elected health facility committee members were trained on their roles and rights in the co-management of primary healthcare facilities. 328 publicly-funded health facilities of Burundi and Sud Kivu in DR Congo were followed over a period of one year. In Kivu, but not in Burundi, the intervention strengthened the position of the committee vis-à-vis the health facility nurses and affected the management of the facility. HFC members mostly focused on improving the elements most accessible to them: hiring staff and engaging in basic construction and maintenance work. Using survey data and interviews, we argue that part of the discrepancy in results between the two contexts can be explained by differences in health facilities’ management (whether they primarily depend on a local church or more distant authorities) as well as different local histories of relationship to public service providers. The former affects the room available for change, while the latter affects the relevance of the citizens’ committee as an acceptable way to interact with healthcare providers. No effect was found on the perceived quality of and access to services, and the committees, even when strengthened, appear disconnected from the citizens. The findings are an invitation to re-think the conditions under which bottom-up accountability mechanisms such as citizens committees can be effective in ‘fragile’ settings.