Over past decades, the World Bank has been criticized by scholars, policymakers, and civil society groups for being unaccountable and inefficient. Confronted with this wave of contestation, the Bank established several internal accountability mechanisms, including the Inspection Panel, the Independent Evaluation Group, and the Compliance Advisor/Ombudsman. Against this background, this article investigates how the proliferation of accountability mechanisms in a large and complex organization such as the World Bank reduces rather than enhances transparency and lines of accountability. I argue that the establishment of a myriad of accountability mechanisms has paradoxically made the Bank even more encapsulated and less accountable to the outside world. Unpacking the differential effects of external and internal accountability mechanisms makes this contribution of significant interest to scholars working on the accountability and performance of international organizations.