How to generate legitimate forms of governance beyond the nation state is not only according to Moravcsik “one of the central questions – perhaps the central question – in contemporary world politics” (2004: 336). To proceed in theory-building, we 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. Thereto, the paper is aiming at 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 IR scholary debate on legitimacy of global governance arrangements and structured by a multi-dimensional concept of legitimacy (input-, throughput- and output-dimension). This framework is then applied to international, transnational and private forms of Environmental Governance in order to show how each of them try to produce and maintain legitimacy, which strategies they apply and in how they interact with their stakeholders. As far as the chosen indicators show a legitimizing effect, they could serve as a standard for upcoming research studies and, by this, contribute to further systematization of studies on global governance. The results with regard to the correlation between certain forms of global governance and, respectively, their legitimacy and acceptance within the international system can form the pre-stage for the formulation of a theoretical explanation of corresponding causalities. The empirical investigation draws on cases from the regulation of forestry.