This thesis analyzes the changing role of the International Energy Agency (IEA) in influencing global energy governance. Taking into account the quick decarbonization, changes in geopolitics and new technologies. It looks closely at the IEA's policy frameworks, market assessments and efforts to reach out to other countries. Highlighting their influence on energy security, renewable energy implementation and conformity with climate policies. Key IEA publications, like, World Energy Outlook, Electricity Market Report and Renewables are used with tools (STEPS, APS, NZE) to evaluate the agency's institutional adaptability in a multipolar energy landscape. Particular attention is directed towards structural constraints, data transparency, predictive accuracy and engagement with non-OECD nations. The thesis states that although the IEA is a vital player in global energy coordination, its continued effectiveness will depend on reforming its governance structure, expanding its geopolitical reach and tackling new challenges like critical mineral security, digitalization and energy justice. The findings improve the understanding of how international institutions should adapt to effectively facilitate the complex transition to a secure, inclusive and sustainable global energy system.