Cultural diplomacy has become a key instrument of soft power for states seeking to expand influence and deepen foreign relations. In this context, Türkiye has strategically utilized shared cultural heritage to shape a distinctive approach toward the Republic of Azerbaijan. This article examines how Türkiye employs cultural diplomacy to strengthen bilateral relations. The main research question explores the ways in which Türkiye has used cultural ties and cultural diplomacy to deepen its political, economic, and strategic engagement with Azerbaijan. The study argues that Türkiye’s cultural diplomacy—anchored in linguistic, historical, and civilizational commonalities—has provided a supportive foundation for advancing the “One Nation, Two States” principle in its foreign policy. Using process tracing, the research identifies the causal mechanisms through which Türkiye activates cultural tools. The findings reveal that initiatives such as expanding Turkish-language education, academic exchanges, the activities of institutions like the Yunus Emre Institute, media cooperation, and the promotion of shared cultural heritage have enhanced mutual identity and increased Türkiye’s social acceptance in Azerbaijan. Ultimately, Türkiye’s cultural diplomacy has strengthened the soft foundations necessary for legitimizing closer bilateral relations and has facilitated the practical realization of the “One Nation, Two States” vision. Data collection relied on written sources including books, scholarly articles, official documents, and online materials.