Taxation is one of the most protected areas of national sovereignty and therefore has great potential of causing obstructive effects on international trade activities. In this respect, the World Trade Organisation is the world's single supervisor of global trade. And of course, the WTO is very well aware of the phenomenon of tax-related distortions of international trade. This book will deal with the WTO provisions relating to taxation and the resulting consequences for a country's latitude to design its fiscal measures. The author will give an introduction to the WTO agreements' legal status within the European Union and the single European Member States. Focus will be on the impact of the WTO regulations in the respective legal orders, which includes an analysis of their legal enforceability. Moreover, the repercussions on individual parties will be addressed as well. Primarily, the book will be dedicated to the GATT and the GATS and their effect on taxation. Great emphasis will be attached to the two major principles embraced therein - Most-Favored-Nation Treatment and National Treatment. In addition, light will be shed on the relationship between the WTO and bilateral double taxation conventions, on the eventuality of conflict and the possible prevalence of one agreement over the other. Finally, non-tax treaties other than the WTO will be addressed. The purpose is to show to what extent these treaties include provisions on taxation or carve-out the issue. Substantially, the author focuses on Treaties of Friendship, Commerce and Navigation, Bilateral Investment Treaties and the Multilateral Agreement on Investment.