This chapter considers the theory’s implications for the significant issue of accountability in global governance. My reasoning may appear to suggest a fundamental tension between performance and accountability: If avoiding the thorniest obstacle to performance requires curtailing state influence in the policy process, international institutions presumably cannot be both effective and accountable. I argue, however, that if we embrace a more expansive understanding of how accountability may be institutionalized, no such tradeoff arises. This is because the same factors that nurture policy autonomy make institutions more likely to adopt a variety of modern accountability structures – what I call second-wave accountability (SWA) mechanisms – that primarily benefit and empower non-state actors. Once in place, moreover, SWA mechanisms can themselves deliver performance gains by revealing operational problems, improving the quality of decision-making, and boosting policy compliance. I provide two forms of empirical support for these claims: (1) statistical evidence based on novel data on the spread and strength of SWA mechanisms; and (2) a qualitative plausibility probe focusing on institutions in the issue area of economic development, where many SWA mechanisms were pioneered.