The principle of abuse of law is expressly regulated in the Czech Republic as one of the basic legal principles in the field of tax law and tax administration. However, its applica-tion is not unlimited and is restricted by the constitutional limits of tax imposition. The article aims to define the limits of its application from the perspective of constitutional conformity. The paper points out the very anchoring of the principle in the legal system, including relevant case law, and analyses possible situations of its application from the perspective of the actions of tax subjects. An integral part of the article is the presenta-tion of specific tax law issues where the principle of the prohibition of abuse of law has been applied across the board in the Czech Republic. In the conclusion, the conflict of the principle of prohibition of abuse of law with the principles of in dubio pro fisco and in dubio pro lebertate is pointed out.