Studies that focus on different urban governance structures, especially unitary states and semi-authoritarian regimes, are still lacking in the urban climate governance literature. This research aims to explain how climate change is governed under a unitary state structure, particularly focusing on how urban climate governance incorporates higher-level government policy and external stakeholders to set a climate agenda and actions. Four main themes are framed from the urban climate governance literature, including agenda setting, the divergence between the existing policies and urban climate agendas, policy entrepreneurs’ roles, and civil society organizations. By focusing on the four themes, we aim to understand how climate change is governed in Istanbul, the biggest and the richest city of Turkey, under a unitary system of government. Based on semi-structured interviews, field notes based on participant-observations, and review of existing official documents, we find that swings in political leadership, the divergence between the existing laws and newly adopted urban climate agendas, and conflicting priorities between policy entrepreneurs generate barriers to long-run and tangible climate change actions in Istanbul. Nevertheless, we argue there is an opportunity space for local governments to co-create new governance mechanisms, as the national government does not have the capacity to lead climate change action, nor is there a political will and focus at the highest levels of government to engage deeply in this policy space.