The rule of "priority of the more important over the less important" is a key principle in Islamic jurisprudence that emphasizes giving precedence to more significant matters when conflicts arise between different issues. This rule is grounded in both religious teachings and jurisprudential reasoning, serving as an essential tool for organizing and prioritizing decisions, especially in complex legal and international contexts. This research presents a comparative and analytical study of the Ahamm and Muhim rule within Shia jurisprudence and explores its application in international law. The theoretical part examines the jurisprudential foundations of the rule and the perspectives of Shia jurists on the role of reason in identifying priorities. It also analyzes how this principle can be applied to resolve complicated legal and international challenges by establishing a hierarchy of issues based on their importance. The study reviews historical and contemporary examples of the rule’s application in international law, demonstrating its practical relevance. Using a library-based research method and data analysis, the findings show that the Ahamm and Muhim rule provides a rational and religious framework that helps Islamic countries make balanced and strategic decisions in the international arena. By applying this rule, Islamic states can enhance their position in the global legal system, improve conflict management, and address global crises more effectively. Ultimately, the research concludes that the Ahamm and Muhim principle strengthens national and Islamic interests and improves the quality of legal analysis and decision-making on the international stage.