The aim of this article is to assess the degree of the implementation of the best practices concerning tax rulings developed under Action 5 of the BEPS Project in Polish tax law. The authors present the current situation of Poland's tax ruling system. Then, the authors assess the degree of implementation of each best practice. The authors also formulate critical comments on the OECD's best practices. In the opinion of the authors, the Polish tax ruling regulation generally meets most of the OECD's requirements, primarily because it is a fully transparent system.

The subject of the opinion is the Supreme Court ruling of 13.09.2018, which provides for the legal qualification of a tip – based on the Act on Income Tax from Natural Persons and the Act on the Social Insurance System. The ruling cannot be considered correct because the Supreme Court formulated a thesis on the sources of tax and contributions financing without referring to the regulations, confining itself to the intentions of the "tip provider" as a key factor influencing the rights and obligations of the payee.