This article examines the transformation of the role of the United Nations under the global processes of the twenty-first century, including climate change, digitalization, geopolitical conflicts, and threats to global health. The research relies on an international legal approach and pays particular attention to the position of the Republic of Uzbekistan as an active participant in the multilateral system. It reviews the institutional and legal mechanisms of the UN and their evolution from classical instruments of maintaining international peace and security toward an expanded set of functions encompassing sustainable development, cybersecurity, human rights protection, and climate-risk governance. Special emphasis is placed on the Global Digital Compact and the climate agenda, which illustrate the UN’s adaptation to the technological and environmental challenges of contemporary international relations. The analysis of Uzbekistan’s contribution shows that the country actively integrates international norms into its national legal system, participates in regional initiatives on sustainable development and water security, and contributes to UN reform. Based on comparative and normative-legal analysis, the article proposes recommendations for improving the UN institutional structure, strengthening regional mechanisms in Central Asia, and integrating international experience into Uzbekistan’s national strategies. The study demonstrates the importance of UN modernization to enhance its effectiveness amid global transformations and highlights Uzbekistan’s role as a constructive partner in shaping a new international legal order.