Museums, along with other public sector organisations, have been urged to co-produce. Co-production may offer increased resourcing and greater effectiveness, and enhances public value through stronger relationships between government and citizens. However, co-production, particularly that which involves collaboration with communities, is largely resisted by public sector organisations such as museums. This research examines the extent to which museums co-produce and the role played by professional bodies in driving or inhibiting co-production. It finds that the study of co-production in museums reveals the influence of 'institutional inertia' and the limits to which professional bodies are able to 'diffuse' co-production and change established professional practice.