The chapter underscores aspects of the study of international organisations (IOs) that are neglected by critical approaches to international law. It calls for an integrated approach that combines external and internal critiques of IOs with proposals for their reform. The chapter argues that the existing literature essentially advances an external critique of IOs with a focus on issues of biased design, the lack of adequate participation of weak states, and unjust distributional outcomes. This critique needs to be strengthened by factoring in the emergence of institutional complexes; by offering a detailed account of the participation of individual postcolonial nations in IOs; by advancing an appropriate theoretical framework that enables spatial, class, gender, race and intersectional critiques; and by suggesting ways to fill gaps in the prevailing accountability regime. The chapter goes on to contend that an external critique must be accompanied by an internal critique of IOs that appraises rules and practices related to membership, withdrawal, suspension, expulsion, voting, finance, and dispute settlement; the changing interpretations of mandates; over time and the role of leadership, staff recruitment policies, knowledge production, and organisational culture. Finally, the chapter calls for an active debate on the need for and ways of reforming IOs.