The article is about studying the role of Italy in the process of Croatia’s accession to the Euro-Atlantic institutions. The purpose of the work is to determine the role of European countries in the process of European integration of post-socialist states and their entry into NATO, using the example of Italian-Croatian relations. The study considered in detail the works and statements of leading Italian scientists and politicians regarding the assessment of the place of the Balkan region in Italy’s foreign policy. The subsequent detailed analysis of the bilateral cooperation of the states helped to identify the key areas their interaction that influenced the rapprochement of Zagreb with the European Union and the North Atlantic Alliance. Ultimately, it was concluded that Italy played a significant role in the integration processes of Croatia, taking several major steps within the framework of Italian-Croatian relations that accelerated the entry of the Western Balkan republic into the EU and NATO. Each of the above points of interstate interaction was considered in detail in order to more accurately identify the specifics of relations between the two countries in the context of expanding Euro-Atlantic institutions. Based on the results of the study, a universal model of cooperation was determined, which can later be used to study other similar cases.