This paper examines the role and impact of civil society in increasing the accountability of the G8 and G20, with particular emphasis on the 2010 summits: the back-to-back June Muskoka G8 and Toronto G20 summits, and the November Seoul G20 summit. The paper begins with a clarification of the key concepts of civil and uncivil society, and accountability. It then discusses for what and to whom the G8 and the G20, as global governance institutions, are accountable. This is followed by a look at the kinds of civil society organizations (CSOs) that play a role in the nexus with the G8 and G20. It then considers the motivations for, and range of, civil society interaction with the G8 and G20. Finally, the paper analyzes how and to what extent civil society engagement has, (or, as the case may be, has not), had an impact on the G8 and G20 accountability. Brief concluding observations end the paper.