Strong evidence suggests that interventions based on community participation have a positive effect on a range of health outcomes in different settings. Community participation contributes significantly to the promotion of health at the local level, especially among the more disadvantaged groups of the society. The main goal of social participation mechanisms is to fill the gap between the views of the policymakers and the experiences and needs of the communities. An important point is that institutionalization of social participation in the development of health policies and its continuity over time are essential requirements. The question here is how participation should be institutionalized in the systems that have started this process. We conducted a realistic evaluation of a multicase study of public participation in health system policymaking. Countries including France, Chile, Iran, Thailand, and Tunisia were selected. The study objective was to determine interventions and mechanisms used by these countries for community participation in health policymaking and institutionalizing it. The data were extracted via a literature review for each country using a realistic approach analysis also known as context, intervention, mechanism, and outcome (CIMO) configurations. Thailand and France, which have applied a set of interventions such as supportive legislations, evidence production structures for informed decision making and interactions, accountability and transparency, and providing a context for development of civil society organizations, have succeeded in institutionalizing community participation in health policymaking. Iran, Tunisia, and Chile have been successful in this regard, but they are still far from institutionalizing community participation. Success in the institutionalization of participatory health governance requires a political will and commitment at the highest level in order to minimize the conflicts between economic and political interests of different stakeholders and to implement a set of interventions to maximize social participation in health policymaking.