This working paper examines the proposed changes to the post-Busan governance structure and provides an analytical framework to assess the merits and challenges for establishing a legitimate governance mechanism for the development cooperation architecture. We argue that the success of Busan in establishing a Global Partnership and making it truly global will depend on the extent to which stakeholders see the governing mechanism as legitimate in terms of its inclusivity, representativeness and effectiveness. Drawing on Graves and Burall’s (2008) tripartite notion of legitimacy as inclusivity and representativeness (input legitimacy), quality of decision-making processes (throughput legitimacy), and effectiveness in achieving outcomes (output legitimacy), we develop a framework to analyse post-Busan governance. We expand on the work of Graves and Burall and examine challenges relating to developing country ownership over the global agenda and capacity for engagement, which are important contributing factors to the legitimacy of the Global Partnership. While our analysis focuses on the HLF processes, it has value for broader discussions on international economic governance where many of the same tensions and trade-offs exist.