The countries of the East Asian region have responded to the challenge of climate change through multiple institutional channels that together form a complex institutional architecture. This fragmented structure resembles the increasing governance fragmentation on the climate change issue area, occurring on the international level. The objective of this thesis is to evaluate the potential for climate change governance within the institutional complex in East Asia. The aim is to contribute to our understanding of under what conditions fragmented governance architectures may be effective means of climate change governance. Based on a rationalist point of departure, this thesis starts by analyzing the interest configuration and power distribution, as well as the potential for leadership, in the East Asian region, in order to determine the demand for cooperation in this setting. Moving on, it evaluates the institutional supply by analyzing the degree of coherence or fragmentation within the structure. Findings indicate that the complexity of institutional arrangements has a comparative advantage in this region, as compared to an integrated approach, but that lack of clear leadership may hamper progress towards deeper cooperation. Traditional mitigation efforts are not high on the regional agenda, but practical cooperation on transition efforts, such as renewable energy and energy efficiency are shared concerns by the powerful actors in the region.