Climate governance has emerged as one of the most contested arenas of international relations, shaped by the tension between global cooperation and hegemonic influence. It sits at the fault line between collective environmental necessity and the enduring hierarchies of global power. This chapter interrogates how hegemony and the position of core states shape the architecture, ambition, and outcomes of international climate cooperation. Focusing on the United States, the European Union, and China, it shows how these actors exercise agenda-setting authority through emissions profiles, financial leverage, technological leadership, and diplomatic influence, thereby steering both the content and tempo of major agreements from Kyoto to Paris. While the UNFCCC framework provides formal universality, its consensus rules and reliance on nationally determined, largely voluntary commitments expose deep limits of multilateralism under asymmetric power conditions. The chapter demonstrates how distributional conflicts over responsibility, finance, technology transfer, and loss and damage repeatedly reproduce North–South inequities, even as hegemonic states portray themselves as indispensable leaders. It also highlights the dual character of hegemony: core states can catalyze innovation and resource mobilization, yet they often dilute enforcement, prioritize domestic political economy, and resist reforms that would redistribute authority or liability. In response to these constraints, the chapter evaluates the rise of alternative governance pathways—climate clubs, minilateral bargains, transnational municipal networks, litigation, and private-sector standards—showing how they can accelerate action while also risking new forms of exclusion. The central argument is that effective and legitimate climate governance requires rebalancing structural power, strengthening accountability for major emitters, and institutionalizing meaningful participation by vulnerable and historically marginalized states. Without confronting hegemonic dynamics directly, global climate governance will remain fragmented, unequal, and misaligned with the urgency of the climate crisis.