The politicized, selective, and discriminatory approach of the Director General of the International Atomic Energy Agency towards the Islamic Republic of Iran and the joint attacks by Israel and the United States on Iranian nuclear facilities led the government of the Islamic Republic of Iran to adopt a multi-layered policy, a strategy of "deliberate ambiguity," and was legally required to suspend cooperation with the International Atomic Energy Agency based on a law passed by the parliament.The present study uses a descriptive-analytical method to examine the legitimacy of the Islamic Republic of Iran's countermeasures against the International Atomic Energy Agency in the post-war period and seeks to answer the question of what measures and strategies the Islamic Republic of Iran adopted after the joint attacks by Israel and the United States on nuclear facilities, and whether these measures are justifiable from the perspective of international law. The study is based on the hypothesis that the Islamic Republic of Iran has adopted a countermeasure against the International Atomic Energy Agency from a legal perspective and a policy of "strategic ambiguity" from a strategic perspective, which is justified by Article 14 of the 2011 International Organizations Responsibility Plan