Tax system in European Union iz regulated by EU member countries, while European Union has only limited powers. The tax policy of the European Union is aimed at achieving the smooth functioning of a single market. Therefore, indirect taxation has been harmonized prior to the adjustment of direct taxation. The constant fight against harmful tax evasion and tax avoidance this becomes a priority objective of the European Union's taxation policy. Member countries must therefore unanimously adopt tax measures, while the European Parliament is the one having the right to advise on tax matters, except in the segment of budgetary matters in which it acts as co-legislator. The thesis consists of several fundamental parts. The introductory part of the thesis presents the subject and purpose of the work, ie. the research methods used in the work and the structure of the work. It then describes the taxation process, that is, the conceptual definition of the taxation process and the key participants in taxation. This is followed by an overview of the EU's general tax policy, with an emphasis on the legal basis, the objectives of the general tax policy and the role of the European Parliament. Chapter four provides a description of the European Union Budget and the principles of the tax system, which emphasize direct and indirect taxes and tax harmonization. Chapter Five introduces taxation trends in the European Union.