In the last few decades environmental problems such as global warming, climate change and ozone layer depletion have been growing and their global impacts have become a major concern. In this regard, various actors including states, international organizations, NGOs, transnational corporations, European Union, United Nations, and transnational movements have become engaged in the process of transnational environmental policy making. Social movements with direct and indirect measures have become an active participant in global environmental governance. The main functions of these movements are raising public awareness, impacting transnational corporations’ policies in order to promote environmental protection, holding international conferences, and influencing state policies, international organizations and epistemic communities. This article reviews the role of transnational environmental movements in global governance.