This chapter discusses the concept of ‘civic epistemology’ in relation to the IPCC and the governance of climate change. Civic epistemology refers to ’the institutionalised practises by which members of a given society test and deploy knowledge claims used as a basis for making collective choices’ (Jasanoff, 2005: 255). Differences in civic epistemologies seem to be directly related to how scientific climate knowledge – presented in IPCC assessment reports – relates to political decision-making at different scales—national, regional, global. The concept is especially rich because it enables a nuanced understanding of the role of IPCC assessments in national climate governance and in meeting the challenges of building more cosmopolitan climate expertise. Both of these aspects are important if emerging institutional arrangements that seek to govern global environmental change are to be understood. Through a critical review of the civic epistemology literature related to the IPCC, this chapter investigates how the cultural dimensions of the science–policy nexus, in different national and geopolitical contexts, conditions the legitimation and uptake of IPCC knowledge.