The OCSDNet Manifesto is a result of one year of participatory consultations and debates amongst members of the ‘Open and Collaborative Science in Development Network’ (OCSDNet), a network of 12 research-practitioner teams from Latin America, Africa, the Middle East and Asia. Through research projects grounded in diverse regions and disciplines, OCSDNet members explore the scope of Open Science as a transformative tool for development thinking and practice and offer the ‘Open and Collaborative Science Manifesto’ as a foundation upon which to reclaim the mainstream narrative about what Open Science means and how it can realise a more inclusive science in development. This paper describes the mechanisms used for collaboration and consensus building, and explores the ways in which the process of building this document serves as a case study for the opportunities and limitations of integrating collaboration, opportunities for participation and openness into research activities.