This article explores the role of the United Nations (UN) within the complex interdependence system of regional security. In an era marked by global interconnectedness and interdependence, regional security challenges necessitate a multilateral approach. The UN, as a global organization, assumes a critical role in addressing these challenges due to its mandate, resources, and convening power. The article begins by elucidating the concept of complex interdependence, emphasizing the intricate web of relationships and interconnections among states and non-state actors in the realm of regional security. It underscores the significance of comprehending the multifaceted nature of contemporary security concerns and the imperative of collaboration and cooperation among nations. Subsequently, the article investigates the UN's role in the complex interdependence system. It examines the UN's mandate, which encompasses the promotion of peace, security, and stability at both regional and global levels. The institutional framework of the UN, including the Security Council, General Assembly, and specialized agencies, provides platforms for dialogue, negotiation, and coordination among member states. Moreover, the article explores the UN's resources and capabilities in addressing regional security issues. It highlights the UN's peacekeeping operations, conflict prevention and mediation efforts, and humanitarian assistance initiatives as crucial tools for fostering regional security. Additionally, it underscores the UN's normative framework, encompassing international law and human rights, as essential components in the pursuit of regional security. Furthermore, the article analyzes the UN's convening power and its ability to bring together diverse actors to collectively address regional security challenges. It discusses the UN's role as a platform for dialogue, diplomacy, and consensus-building, facilitating regional cooperation and fostering trust among states. Lastly, the article acknowledges the limitations and challenges faced by the UN within the complex interdependence system of regional security. It recognizes the need for ongoing efforts to enhance the UN's effectiveness, responsiveness, and adaptability to evolving security dynamics. In conclusion, this article underscores the indispensable role of the UN within the complex interdependence system of regional security. By leveraging its mandate, resources, and convening power, the UN significantly contributes to the cultivation of peaceful and stable regional environments in an era characterized by interconnectedness and interdependence.