Dilemmas from climate change to financial meltdowns make it clear that global interconnectedness is the norm in the twenty-first century. As a result, global governance organizations (GGOs)—from the World Trade Organization to the Forest Stewardship Council—have taken on prominent roles in the management of international affairs. These GGOs create and promulgate rules to address a host of pressing problems. But as reveals, they struggle to meet two challenges: building authority despite limited ability to impose sanctions and maintaining legitimacy while satisfying the demands of key constituencies whose support is essential to a global rulemaking regime. Through a novel empirical study of twenty-five GGOs, Jonathan GS Koppell provides a clearer picture of the compromises within and the competition among these influential institutions by focusing attention on their organizational design. Analyzing four aspects of GGO organization in depth—representation and administration, the rulemaking process, adherence and enforcement, and interest group participation—Koppell describes variation systemically, identifies patterns, and offers explanations that link GGO design to the fundamental challenge of accountability in global governance.