There is an increasing recognition that to avoid dangerous climate change, most fossil fuel reserves will need to be left in the ground. This calls for increased attention for policies focusing on the supply side of fossil fuels. While national policies play a key part in governing fossil fuels and any transition away from them, international institutions can also play an important part. This paper starts by examining how different international institutions govern fossil fuel extraction and the extent to which their governance approaches overlap, complement or conflict with one another. It maps the institutions according to their objective, governance functions and activities relevant to fossil fuel development, to get an overview of the existing roles of international institutions. The paper then examines the potential role some of these institutions can play in governing the transition away from fossil fuel extraction, focusing in particular on options to address the supply side of fossil fuels within the United Nations Framework Convention on Climate Change (UNFCCC) and the World Trade Organization (WTO).