Most scholars treat NGOs as a homogenous group and base their theoretical and normative arguments around such a generalization, even when recognizing that NGOs vary significantly on a number of levels. This Article seeks to advance the literature on NGO accountability by unpacking NGOs by functional role in international governance, relating the functional roles of NGOs to accountability theory. This Article proposes that participation of NGOs in international governance should not always depend upon democratic accountability. Instead, the accountability required of NGOs when participating in international governance should depend upon the particular function performed. As a result, the accountability mechanisms used to achieve such accountability will necessarily vary by function. Failing to recognize this, theories which elaborate theories of NGO participation in international governance, have missed the mark, focusing primarily on ensuring greater accountability of NGOs generally. This Article seeks to remove the debate from the provision of accountability from the level of the actor to that of function.Part I begins with a discussion of accountability in international governance, establishing a general typology of accountability mechanisms, based largely upon the work of Grant and Keohane. Part II then describes some of the different functions performed by NGOs in international governance, providing examples of how such systems are arranged under existing frameworks and illustrating the relationship between the function performed and the accountability needed. Part III seeks to refine NGO accountability theory by proposing a new model to guide NGO participation in international governance which links accountability to function. Part III also identifies some concerns in implementing the theory. The Article concludes by calling for further research into the costs of implementing this new framework so an appropriate balance between fairness, operability, and accountability may be reached in international governance.