Polycentric governance networks are on the rise in global energy and climate governance, but we know surprisingly little about their effectiveness. This paper analyzes the performance of four such transnational energy and climate governance networks. In the realm of sustainable energy, our cases are the Renewable Energy and Energy Efficiency Partnership (REEEP) and the Global Alliance for Clean Cookstoves (GACC). In the climate sphere, we examine the effectiveness of the Green Climate Fund (GCF) and the Clinton Climate Initiative (CCI). Using principles from governance and public administration about the effectiveness of institutions, we examine the extent to which four networks have contributed to improving governance outcomes in the spheres of climate and sustainable energy. Our evaluation focuses on the clarity of purpose, funding, institutional formality, efficacy, and level of resilience of these networks. Some differences between the networks notwithstanding, we find that the transnational governance networks generally fail to meet the criteria about what constitutes an effective institution. The paper concludes with a reflection on what could be done to enhance the performance of these governance networks. governance 3. Polycentric governance assessment framework Polycentrism, a form of governance that blends scales and/or types of actors (Visseren-Hamakers, 2015; Galaz et al. 2012) is related to the more recent literature on 'network governance' and 'governance networks'. McGinnis and Ostrom (2012) note that the concept of polycentricity, first laid out by Michael Polanyi (1951) and later adopted by Vincent Ostrom et al. (1961), can be seen as an early statement of the critical importance of network forms of governance in democratic societies. Yet, the more recent literature on network governance and governance networks rarely makes any mention to this pioneering work (Klijn and Koppenjan, 2012), despite the similarity of the concepts. Nonetheless, the'governance networks' that are formed by actors from the state, the market and civil society to address climate change can be said to provide 'polycentric governance' in the sense that they include the self-organizing relationship between many centers of decision-making that are formally independent of each other (Ostrom et al., 1961: p. 831;Ostrom, 2010).In this section we propose four criteria, drawn mostly from the literature on public administration, policy sciences, and governance, to assess the performance of polycentric energy and climate networks, building on an earlier study by Poocharoen and Sovacool (2012). We employ the term 'performance', which allows for a more contextualized evaluation compared with the concept of 'effectiveness'. Whereas effectiveness usually refers to 'outcome' (i.e., goal attainment), performance refers more to 'process' (i.e., the manner by which outputs and outcomes are achieved). Here, we argue it includes the ability of the network to (1) set clear goals; (2) mobilize resources; (3) adopt formal structures; (4) make int...