The experience of civil society in the Global Fund to Fight HIV/AIDS, Tuberculosis and Malaria (GF) represents one of the rare occasions in international development history when civil society organizations have played a key role in the establishment of a multilateral organization and gained formal voting representation in its governance. Civil society is represented both in the global board and in the national Country Coordinating Mechanisms of the GF. This chapter examines whether and how civil society groups have promoted accountability in the GF and how those associations are strengthening their own accountability to their constituents. Given the particular vulnerability of women and girls to the three diseases, a key part of this examination is the extent to which the GF has integrated gender considerations into its operations and the role civil society is playing in this regard. The analysis is conducted along four dimensions: doing no harm at a minimum; promoting the organization’s goals; taking responsibility; and correcting mistakes through evaluations and sanctions. The first two aspects require voice or participation, while the latter two involve transparency and mechanisms of monitoring and regulation. The chapter argues that CSOs are an integral part of the GF, contributing to its resource mobilization, expanding transparency, ensuring that the priorities of primary stakeholders drive funding decisions, and contributing to sustainability of programs and the organization overall. The challenge for civil society actors continues to be to strengthen accountability to their own constituencies so as to be truly representative and legitimate actors in the governance of the GF.