Significant climate changes are foreseen in the coming years alongside major impacts of frequent and extreme weather conditions affecting cities, residents, and urban infrastructure systems. In parallel, demographic changes and increased urbanization are anticipated given that most of the world’s population is expected to be residing in cities in the following decades. Therefore, adapting urban areas remains an urgent matter as cities are susceptible and vulnerable to climate change on one hand, and are exposing a large and an increased number of dwellers to major impacts on the other hand. This research focuses on medium-sized European cities, hosting millions of people and exposing them to the major impacts of global warming. These cities could be at disadvantage in comparison to larger cities given that they could have limited technical, financial, and human resources. However, they also present certain advantages as addressing the issue seems more manageable in limited geographical areas, in comparison to metropolitan areas. Additionally, small administrations benefit from straight and short lines of communication. The selected unit highlights the severity and magnitude of climate-related issues in urban areas and underlines the urgency to act. It also sheds light on the role of local governments and municipalities in addressing a topic of global relevance. Experimenting locally with adaptation approaches could present both opportunities and challenges given that climate change is a global issue. Hence, questions are raised to deduce the way forward in the governance of climate change adaptation in medium-sized cities. This study adds to the existing literature by underlining the impacts of climate change on urban systems in the selected mid-sized European cities. It also investigates the role of local municipalities and governments in developing and implementing environmental and adaptation action plans. For this purpose, a comparative case study approach is adopted, focusing on five medium-sized European cities: Växjö (Sweden), Nijmegen (the Netherlands), Leuven (Belgium), Rouen (France), and San Sebastian (Spain).This approach sheds the light on various methods employed by local governments to understand impacts, develop corresponding strategies, mobilize actors, implement developed strategies, monitor, and evaluate adaptation progress, understand barriers to implementation and improve the governance system in place.An urban climate adaptation governance index is developed allowing to assess whether governance efforts have contributed to ensuring the adaptability of mid-sized European city and increase their resilience to climate events. This index is applied to each of the selected case studies to quantify and benchmark their efforts against one another. The results of the comparison of the selected mid-sized cities reveal the importance of the collaboration of local authorities with local experts and universities to bridge knowledge gaps in climate adaptation, map vulnerability, and raise public awareness. They also underline the importance of adopting a strategy of anticipation of risks and adaptation to climate change instead of taking reactive measures. The comparative analysis stresses the need to adopt a participatory governance approach, embrace opportunities, turn strategies into action plans and concrete measures, and experiment with small-scale initiatives. It also stresses the need for systemic changes as well as changes to the way mid-sized cities are designed and governed. The results introduce the importance of developing monitoring and evaluation systems as well as indicators dedicated to assessing adaptation efforts. Lastly, they underline the significance of reporting to the public on the progress of adaptation measures and developing a long-term vision as well as contingency plans to build preparedness and increase climate resilience.