Abstract
<jats:p>The article substantiates the theoretical and methodological role of Euroregions in shaping cross-border diplomacy for sustainable development within the framework of Ukraine’s European integration processes. Based on the analysis of contemporary scientific approaches, EU legal acts, and the practices of the Interreg, LIFE, and Horizon Europe programs, results were obtained that reveal the specifics of Euroregions’ participation in paradiplomatic and cross-border interactions, the institutional and functional mechanisms for adapting European sustainable development standards at the subnational level, and the forms of implementing the principles of “bottom-up diplomacy.” A conceptual model of the institutional development of Euroregions was developed, built on the study of the evolution of their institutional formation in the European and Ukrainian contexts and the specifics of their involvement in the system of paradiplomatic and cross-border interactions. The scientific novelty lies in conceptualizing cross-border diplomacy for sustainable development as a tool of multilevel governance, integrating the institutional, functional, communicative, and diplomatic dimensions of Euroregions’ activities, and identifying mechanisms for localizing the Sustainable Development Goals through networked governance, polycentric interaction, benchmarking of European practices, and activation of interregional coordination. The results of the study are of practical importance for improving the effectiveness of Ukrainian Euroregions’ participation in EU programs, as well as for strengthening the institutional capacity of local authorities in implementing the principles of subsidiarity, partnership, and polycentric governance. In the context of war, cross-border diplomacy through Euroregion mechanisms takes on particular importance, facilitating the coordination of humanitarian aid, the development of logistical links, and the strengthening of cooperation with European partners.</jats:p>