The evolving geopolitical landscape of the South Caucasus in recent years has created significant opportunities for Turkey to expand its influence and advance its strategic interests in the region. This article examines Turkey’s policies in the South Caucasus and assesses their implications for the national interests of the Islamic Republic of Iran. The central research question investigates how Turkey’s regional strategies affect Iran’s national interests. Drawing on the theoretical framework of constructivism, the study hypothesizes that Turkey’s policies in the South Caucasus have directly and indirectly weakened Iran’s political, economic, and cultural influence in the region. The findings indicate that Turkey has sought to strengthen its regional position by employing identity-based instruments, including shared cultural, linguistic, and historical ties. While these strategies have enhanced Turkey’s strategic standing in the South Caucasus, they have also posed multidimensional challenges to Iran’s national interests. Methodologically, the study adopts a descriptive–analytical approach and relies on library sources and online databases for data collection.