Using neoclassical realism as its theoretical framework, this study aims to explain the changes in Bulgarian foreign policy during the post-communist processes. While the communist regimes in Eastern Europe and the Balkans were collapsing in an environment where the balance of power would change with the triggering of systemic effects, this power vacuum led the former Eastern Bloc count-ries to seek new foreign policies. In this context, the main research questions involve how the pro-Euro-Atlantic foreign policy of Bulgaria can be explained as a former Eastern Bloc country after the Cold War and how the intra-state factors and leaders affected the transformation process of foreign policy. The post-communist period saw significant changes in Bulgaria’s domestic and foreign policies. While new le-ader profiles emerged in domestic politics, pro-EU and NATO political formations were included in the political arena. In this change process, the Turkish and Muslim minorities assumed important roles in the political system and supported pro-EU and NATO policies. Although the Bulgarian Communist Party tried to carry out the representative policies of the past in this process, it could not resist the changes in domestic and foreign policies. Political parties founded by minorities and new poli-tical formations advocating European integration were two of the central dynamics of change at the intra-state level. Neoclassical realism considers the power changes within the international system while also including intra-state factors in its analy-ses. Neoclassical realist theory provides the opportunity to deal with the change in Bulgaria multidimensionally and opens an important area for leaders. Neoclassical realism offers a more systemic and comprehensive analytical framework by inclu-ding internal factors in analyses regarding explaining the changes in foreign policy.