This thesis takes a dynamic approach to the treatment of energy in international trade law. It traces the development of energy rules from the inception of the 1947 General Agreement on Tariffs and Trade (GATT) to Trans-Atlantic Trade and Investment Partnership (TTIP) negotiations today. The thesis is divided in two main parts: (I) Regulation and (II) Challenges. The first part of the thesis discusses the controversies surrounding the coverage of energy in the GATT/WTO forum. It continues by providing an overview of WTO Agreements relevant for the treatment of energy. Finally, this part of the thesis looks at the crystallization of new rules in energy trade: what developments do we observe in WTO accession commitments and, beyond the WTO, in preferential trade agreements? In the second part, the thesis focuses on three major challenges in WTO law with respect to energy. It starts off with a comparative study of the WTO and the Energy Charter Treaty (ECT), scrutinizing their overlap and potential conflict. Then, using law and economics methodology, the thesis takes a closer look at restrictive practices in energy trade, such as those maintained by Members of the Organization of the Petroleum Exporting Countries (OPEC). Third, this part discusses the 'subsidies paradox' in WTO law through which fossil fuel subsidies arguably escape the disciplines of the WTO. Subsidies for clean energy and renewables, on the other hand, are an easy target for WTO dispute settlement proceedings. By way of conclusion, the thesis considers policy options for enhanced energy governance. It, amongst others, discusses possible future scenarios and the role of the WTO and Energy Charter Treaty therein.