Based on empirical fieldwork, this article analyzes the negotiation of a Framework of Engagement with Non-State Actors (FENSA) at the World Health Organization (WHO) between 2011 and 2016. The study examines the long and difficult negotiation process, which shifts from a mere adaptation of guidelines by the WHO Secretariat to an intergovernmental negotiation led by a core group of Member States. This negotiation process cannot simply be explained by traditional dialogues among delegations and hierarchical relationships within international organizations. Other factors played important roles in the process as well – the high political stakes of the issue, non-traditional coalition games, heterogeneity among the actors, and the WHO Secretariat’s role as a negotiating party – all advocating for the development of a triangular, multi-voice negotiation model within international organizations.