This research critically assesses the contributions of Environmental International Organizations (EIOs) - such as the United Nations Framework Convention on Climate Change (UNFCCC), United Nations Environment Programme (UNEP) and World Meteorological Organization (WMO) - to climate mitigation and adaptation in the context of the Sustainable Development Goals (SDGs). Through a comprehensive review of peer-reviewed articles and institutional reports between 2018 and 2024, the paper examines govern