Due to the unanimity requirement in the Treaty on the Functioning of the European Union (TFEU), the harmonization of the national rules on direct taxation is still in an undeveloped state. Nevertheless, the fundamental freedoms form a framework for national tax legislation with regard to intra-Union situations. The role of the European Court of Justice is not to replace the legislator but to provide an interpretation of the Treaty rules which, on the one hand, takes into account the particularities of national taxation and, on the other, ensures the effectiveness of the provisions of EU law. After an introduction to the structure and functioning of the Court, as well as an overview of the various ways in which the fundamental freedoms impact on national legislators’ choices in matters of taxation, the course focuses on the presentation and analysis of the recent case law (both judgments and Opinions of Advocates General) in the field of direct taxation. The aim is to explain the reasoning of the Court as well as to identify common lines in its decisions. In as far as the Court has already dealt with specific features of international taxation (e.g. CFC regulations, bilateral tax treaties), the course supplements other parts of the LL.M. program.