The purpose of the article is to study the existing taxation systems in order to work out the results of their effectiveness. The following methods were applied within this article: dialectical method, historical and hermeneutic methods, systematic method, formal-legal method, logical method, direct method, induction and deduction method, modeling and system analysis method, axiomatic method, and others. The results of the study are the definition of basic concepts and terms: tax, taxation system, international taxation system; the need for the existence of an international taxation system has been established; the EU tax system has been analysed; two major international taxation systems have been characterised; a study of the Albanian tax field has been performed. The terms laid down in this article are of practical value for public authorities and people in charge whose powers include the improvement and reform of the tax system of Albania, as well as for individuals and legal entities that are, to one degree or another, participants in tax relations.