The foreign policy of the Islamic Republic of Iran during the past three decades has witnessed a variety of developments and trends. This, in a way that even within the framework of basic and fixed fundamentals and principles, Iranian foreign policy has shown different behaviors. On the other hand, despite the changes and developments in the domestic and international arenas, some behaviors on the part of Iran have remained unchanged. Thus, there has always been a fundamental question: what is the main motive and reason for the behavior of Iran via its foreign policy? In response to this question, the theories analyzing foreign policy and international relations explain the motives for Iran’s behavior on the basis of the concept of physical security. However in this article, the behavioral motive and reasoning behind Iranian foreign policy are analyzed based on the ontological security theory. Through this prism, the most important behavioral motives of the foreign policy of the Islamic Republic of Iran during conflicts are to consistently seek and ensure ontological security. Meaning, Iran, in its foreign policy, is more concerned about preserving its own identity as an Islamic state and gives preference and priority to ensuring ontological security which translates into preserving and sustaining Iran’s Islamic identity.