In 2014, the International Public Sector Accounting Standards Board (IPSASB) published its first ever conceptual framework. Although the IPSASB generally follows a convergence strategy with the International Financial Reporting Standards (IFRS), the board decided to diverge from this strategy to develop a public sector specific framework and subsequently identified accountability and decision usefulness as objectives of public sector financial reporting. This qualitative empirical study investigates why the IPSASB decided to develop a public sector specific framework and how it identified accountability and decision usefulness as objectives. Analyzing the organization of international financial reporting in the public sector and the involvement of different actors in standard-setting, the study at hand shows that the board’s actions were aimed at strengthening its technical and political legitimacy. Moreover, the study reveals that the IPSASB’s due process relied heavily on individuals from national standard setters and the staff as core resource providers of experiential expertise, while the public consultations were used to obtain verification of internal deliberations. It concludes by arguing that the publication of the conceptual framework provides the IPSASB with the opportunity to further strengthen its legitimacy as international standard setter of public sector financial reporting.