How to generate legitimate forms of governance beyond the nation state is often considered a central question in contemporary world politics. To proceed in theory-building, scholars need to systematically assign the theory-driven assumptions on legitimate forms of governance beyond the nation state with the various, already observable, forms of global governance. This article aims to conduct a comparative appraisal of the legitimatory quality of different patterns of governance by applying a framework of indicators for their assessment. The indicators are selected from the scholarly debate within International Relations on the legitimacy of global governance arrangements and structured by a multidimensional concept of legitimacy (input, throughput, and output dimensions). This framework is then applied to international, transnational, and private forms of global governance in the field of Internet regulation in order to show how each of them tries to produce and maintain legitimacy, which strategies it applies, and in how it interacts with its stakeholders.