The evolution of international trade rules has been a defining factor in shaping contemporary global economic relations, particularly through the establishment of a rules-based multilateral trading system. Against this background, the present study examines the institutional role of the World Trade Organization (WTO) and its influence on both developed and developing countries. The objective is to analyze how international trade rules affect economic stability, predictability, and equitable participation in global trade, while identifying key legal and institutional challenges facing the multilateral trading system. The research employs a qualitative approach based on doctrinal legal analysis, complemented by analytical and comparative legal methods. Core WTO agreements and selected multilateral, bilateral, and regional trade instruments are examined, together with relevant WTO practice and scholarly literature. The results indicate that adherence to binding commitments, the credibility of the dispute settlement mechanism, and the growing participation of developing countries significantly contribute to the effectiveness of the rules-based trading system. At the same time, stalled multilateral negotiations, the influence of domestic interest groups, and the proliferation of regional trade agreements pose persistent challenges to the coherence of global trade governance. Overall, the study concludes that the future of global economic stability depends on the continued effectiveness and adaptability of international trade rules, as well as on a renewed commitment of WTO members to multilateral cooperation. Strengthening the rules-based trading system remains essential for ensuring fairness, predictability, and inclusive integration into the global economy