Given the important role and influence that the Islamic Republic of Iran has in the developments in the West Asian region, the use of deterrence policy and defense diplomacy to repel threats is considered a strategic issue. This type of deterrence policy is influenced by the doctrine of Ayatollah Khamenei, who believes that in the field of defense and deterrence, all governments and nations need security and should play a role in designing a public security model and protecting it. The question raised in this article is what components does Iran's deterrence policy in the West Asian region contain based on the Supreme Leader's defense diplomacy strategies? The results and findings of the article show that in the Islamic Republic of Iran, defense cooperation stems from the country's foreign policy framework. In such a case, the goals of defense diplomacy are subordinate to the general goals of foreign policy, and defense diplomacy is a subset of foreign policy. Accordingly, the country's defense diplomacy stems from the principles and teachings of Ayatollah Khamenei. Defense diplomacy in the leadership's thinking is based on three principles: brotherly relations with Islamic countries, dealing with enemies, and peaceful relations with friendly countries. The pillars of Iran's defense diplomacy and fruitfulness from the leadership's perspective are: "fighting the system of domination", "military and defense cooperation", and "strengthening military alliances in the Islamic world".