Shortly after the establishment of the Republic of Cyprus, the events initiated by Makarios’ attempts to amend the constitution, which escalated into internal conflicts and external interventions, culminated in Turkey’s military intervention. The effects of this intervention continue to persist today. Due to this characteristic, it has been the subject of many studies; however, it has not been evaluated in terms of the jus cogens rules, which express the universally accepted principles of international law, and the stages of the just war theory. To address this need, the 1974 Cyprus Peace Operation, a long-standing international issue, has been examined within the framework of the jus cogens rules of international law, considering the three phases of just war theory: jus ad bellum, jus in bello, and jus post bellum. This examination aims to determine the level of compliance with jus cogens international law norms in the historical and political context of the Cyprus issue, as well as the developments before, during, and after the 1974 Peace Operation. Consequently, it has been determined that the 1974 Peace Operation adhered to the jus cogens rules of international law to the maximum extent. In the source review, a balanced selection of sources was made to objectively evaluate the assessments of both the Turkish and Greek Cypriot sides on the issue. This study is qualitative in nature, employing both inductive and deductive methods.