Since ten years ago, with the construction of the so-called Ilisu dam at its southern borders, the Turkish government has threatened the environmental security of its neighboring countries, including Iran and Iraq. This paper, using a descriptive-analytical approach and collecting the required data through library method and then analyzing them, seeks to investigate the contradiction between the construction of the Ilisu dam project and the international rules and obligations of that state. Research findings have also shown that the Turkish government has violated the rules and regulations of international law about its border neighbors by constructing the dam. Non-compliance with customary international law, International Public Law provisions, including the Convention on Environmental Assessment of Transboundary Movements, the Declaration on Environment and Development (Rio Declaration), the World Bank's legal standards, as well as Turkey's bilateral agreement with the Iraqi government on the Tigris and Euphrates and European Regional Obligations such as the European Convention on Human Rights and Fundamental Freedoms, are examples of the illegality of the Turkish government's actions. In this regard, it is proposed that the governments of Iran and Iraq, while negotiating and exerting a diplomatic pressure on the Turkish government to prevent the construction of the dam, will put the Turkish government under pressure via broadcasting the threats and consequences of the Ilisu dam construction. In addition, raising issues in international organizations, especially the United Nations, can play an important role. In the security and law enforcement area, the readiness to deal with any moves in the event of exploitation of the dam should be considered.