The development of the international environmental regime has been significantly influenced by multilateral diplomacy, with landmark conferences such as Stockholm (1972) and Rio de Janeiro (1992) establishing key norms and principles of international environmental law. The non-binding but impactful provisions of the Stockholm Declaration and Rio Declaration have been codified further in international environmental treaties that are characterized by a “framework approach” allowing for the use of general arrangements accompanied by dynamic implementation and adaptation through protocols and annexes. These treaties emphasize collective global responsibility while recognizing environmental protection as a common interest. Periodic Conferences of the Parties (COPs) under the UNFCCC exemplify the significance of multilateral diplomacy in advancing global environmental efforts. COP29, to be held in Azerbaijan in 2024, underscores the critical importance of such diplomacy in addressing pressing environmental challenges. This paper examines the role of multilateral diplomacy in shaping the international environmental regime and highlights the necessity of shared responsibility and collective efforts. It emphasizes the evolution of international environmental law and the importance of flexible, adaptive treaty frameworks in addressing global environmental problems.