A number of papers have focused on UN policy formulation processes, but little is known about how particular issues come to policy-makers' attention in the first place. This very early stage of policy formulation, called agenda setting, remains under-researched and more so in multilateral contexts. Applying Kingdon's multiple streams model to the example of the Decade of Education for Sustainable Development (DESD), this study analyses the trajectory of the policy from being just an idea to the point of being placed on the UN agenda. This paper goes on to argue that there are three conditions that supported the successful trajectory of DESD: a funding-backed policy entrepreneur, policy oligopoly, and a highly predictable policy window. Its theoretical contribution is to fill the gap between current studies and theories by presenting an analysis of one policy in a multilateral context.