The role of cities in sustainable development has gained increasing importance since the adoption of the Rio Declaration and Agenda 21, culminating in SDG 11 of the 2015 UN 2030 Agenda. Among the challenges of urban sustainable development, climate change has been recognized as a central one, positioning cities as fundamental actors in mitigation and adaptation efforts. In parallel with discourse on sustainable cities, the concept of smart cities has been presented as a tool aimed at improving urban resilience through technology and data‐driven decision‐making. The article investigates whether climate neutrality is becoming the new imaginary of sustainable cities, by analysing the emergence, development, and future perspectives of the dominant sustainable and smart city imaginary in the governance of sustainable development, both at the international and European levels. We review the main scholarly literature and policy documents by tracing the evolution of ideas, practices, and policies that have shaped the modern concept of the sustainable city. We then examine how this concept has expanded to include concerns about climate change adaptation and mitigation through smartness, often overlooking the issue of social inclusion for the most vulnerable.