The use of chemical weapons is considered one of the most prominent examples of the violation of fundamental rules of international humanitarian law and international criminal law, having devastating and uncontrollable effects on humans, the environment, and international peace and security. These types of weapons, with their capacity to cause death, severe physical injuries, and widespread contamination, have long been a concern for the international community and have led to the adoption of numerous international treaties, including the 1925 Geneva Protocol and the 1993 Chemical Weapons Convention. However, despite the explicit and universal prohibition of the use of these weapons, numerous instances of their deployment in contemporary armed conflicts, particularly in the Middle East, have been documented, posing serious challenges to international criminal mechanisms. The main question of this research is: what is the international criminal responsibility arising from the use of chemical weapons, and what challenges does the international criminal justice system face in prosecuting and punishing the perpetrators of this crime? This article, aiming to examine the international criminal dimensions of the use of chemical weapons, analyzes legal concepts, the bases of individual criminal responsibility, the role of international courts, principles of universal jurisdiction, and the challenges in prosecuting the perpetrators of this crime. Furthermore, by evaluating the performance of institutions such as the International Criminal Court (ICC) and the Organisation for the Prohibition of Chemical Weapons (OPCW), it seeks to provide solutions for strengthening international enforcement guarantees and improving the effectiveness of the criminal justice system in dealing with this crime. The findings of this research indicate that the use of chemical weapons not only constitutes a war crime and a crime against humanity but also entails serious legal consequences from the perspective of the international responsibility of states, which requires more effective cooperation among countries, enhancing the capacities of supervisory bodies, and removing political and legal obstacles in the criminal prosecution process.