Abstract. The article analyzes the transformation of Iran’s foreign policy strategy from the Islamic Revolution of 1979 to the early decades of the twenty-first century. Particular focus is placed on how domestic reforms, constitutional changes, and shifting geopolitical conditions shaped Tehran’s external orientation. The study highlights the central role of the Supreme Leader, whose broad constitutional powers allow him to define national priorities, supervise their implementation, and intervene directly in political institutions. It further examines the contributions of the President, the Parliament (Majles), the Foreign Ministry, and constitutional councils to policy formulation. The paper traces key stages of Iranian diplomacy under Rafsanjani’s pragmatic reconstruction, Khatami’s “Dialogue Among Civilizations,” Ahmadinejad’s confrontational justice-centered approach, and Rouhani’s moderate, economically oriented strategy culminating in the JCPOA. Overall, the research demonstrates how Iran’s foreign policy continuously balances ideology and pragmatism to strengthen national interests and ensure regional leadership.