This chapter outlines the different dimensions of non-governmental organizations (NGO) accountability through the analytical lens of stakeholder theory, which is the most common frame used by practitioners and scholars. It focuses on the practical issues of implementing accountability by identifying different mechanisms and procedures associated with each set of stakeholders. The chapter discusses the emergence of the accountability agenda from the end of the Cold War. It examines upward accountability, downward accountability, internal accountability and horizontal accountability. The accountability agenda is shaped by complex configurations of motivations, relationships and mechanisms. Downwards accountability is used to describe the accountability responsibilities that NGOs have towards the people and communities that they represent and serve. Organisations attempt to implement downwards accountability at strategic points in the project cycle. NGOs are the ‘organizational expression of their members’ ethical stance towards the world’, but accountability to members tends to be overlooked in the literature.