The Open Government Partnership (OGP), donors and multilaterals, and social accountability practitioners across the world are among various constituencies attempting to harness and actualise emerging insights about the nature of successful governance reform. But each of these groups faces challenges as they do so. This brief reviews the evidence from Learning to Make All Voices Count (L-MAVC), a programme funded by Making All Voices Count, and implemented in collaboration with Global Integrity. L-MAVC intended to support six Making All Voices Count grantees, working in five countries, in co-creating and applying a participatory, learning-centred, and adaptive approach to strengthening citizen engagement in governance processes in their contexts, including with respect to the Open Government Partnership (OGP). Two sets of lessons emerge from the experience of L-MAVC. First, supporting citizen engagement and government accountability in subnational contexts, and localising OGP in ways that matter to citizens, is not straightforward. Doing so successfully entails engaging with, navigating and shaping political and power dynamics in those contexts, and iteratively adapting to emerging lessons and challenges. Second, the effectiveness of adaptive ways of working depends in part on the extent to which they offer opportunities for cross-context peer learning, support the regular collection and use of data, and are themselves adaptive. These lessons have implications for the broader community of actors working to support governance reform, including OGP and its partners, donors and multilateral institutions, and practitioners and policy-makers. If these actors are to contribute more effectively to reforms that affect citizens’ lives, substantial changes – with respect to the nature of support provided to domestic stakeholders, grant-making practices, and practitioner approaches – may be warranted.