Does the taxpayer have a chance to win against the tax authority?

This article concerns the principle of in dubio pro tributario in tax law (Article 2a of the Tax Ordinance). The legal provision regulates the resolution of doubts in favour of the taxpayer. The scope of application of the principle has been narrowed to doubts about the content of tax law provisions that cannot be removed. The article is divided into five main parts: an introduction, three chapters and a conclusion. Chapter I covers the genesis normative basis of the in dubio pro tributario principle. The author briefly indicates there that the principle has a longer history, but focuses on the history of the principle in the Polish legal system. In Chapter II there are analysis of the content of the provision, in order to obtain the fullest possible knowledge on the application of the regulated principle. The views of doctrine are juxtaposed there and the issues of application of the principle are indicated. Chapter III is a juxtaposition of art. 2a Tax Ordinance with the general principles of tax proceedings selected by the Author and the notion of tax justice. The author's opinion is revealed in the conclusion, where she also determines how the discussed regulation should be applied. This may be the case when, after linguistic, systemic and functional interpretation only, doubts remain as to the content of tax law provisions. The principle is a postulate for reliable establishment and application of tax law. The study uses a dogmatic and legal research method and analysis of the literature on the subject.