This article develops a sectoral approach to the analysis of global climate governance. This approach advances the assessment of global climate governance by focusing on complexes of intergovernmental and transnational institutions co-governing key socio-technical sectoral systems. The actual and potential contribution of these sectoral institutional complexes to advancing decarbonization can be assessed according to five key governance functions: (1) providing guidance and signal to actors, (2) setting rules to facilitate collective action, (3) enhancing transparency and accountability, (4) offering support (finance, technology, capacity-building), and (5) promoting knowledge and learning. On this basis, we can assess the potential of international cooperation to address the challenges specific sectoral systems face in the climate transition as well as the extent to which existing sectoral institutional complexes deliver on this potential. This provides a solid starting point for developing options for filling identified gaps and enhancing the effectiveness of global climate governance.