This innovative academic project evaluates the impact of transnational cities’ networks on European migration policies and develops guidelines in cooperation with politicians and practitioners to strengthen their work in the European multi-level governance system. To this end, the activities of formal and informal transnational cities’ networks are examined. A special focus is placed on the EUROCITIES network, from which the movement of Solidarity Cities originated. This movement aims at demonstrating cities’ political leadership in light of integration and relocation challenges within the European Union. Besides, the EUROCITIES build the Council of European Municipalities and Regions, which is the European umbrella organisation of municipal associations in the member states. The guiding research question of this study is: How do city networks influence integration and migration policies on EU-level? This study analyses both network activities and strategies of individual network members, such as Athens (Greece), Barcelona (Spain), Munich (Germany), Gdansk (Poland), Ljubljana (Slovenia), Vienna (Austria), Amsterdam (Netherlands), Nantes (France) and Palermo (Italy). A mixed-methods approach is applied, combining the analysis of policy documents and expert interviews. The latter include interviews with experts of the EUROCITIES network as well as the local and the EU level. Hence, the aim of the project is threefold. Firstly, it offers insights into the strategies the different cities pursue and the transnational relations they use in accordance to their interests. Secondly, it evaluates the mechanisms initiated by the municipal associations with regard to their specific target. Thirdly, guidelines are developed in cooperation with politicians and practitioners and published in policy briefs, which are presented in a final meeting in Brussels. Due to the current brisance of this topic, its highly innovative perspective on the making of EU migration policies and the lack of research in this area, this project will set a milestone in understanding the role and power of municipal associations in a newly unfolding sphere of European multi-level migration governance.