The subject of this study is the mechanism of implementation of the regulatory function of a tax, the study of this function in the system of tax functions, as well as the identification of the need to identify sub-functions of the regulatory function of a tax, which is designed to have an indirect effect on various spheres of public relations, stimulating or discouraging a certain pattern of behavior. For a long time, the fiscal function of taxation has dominated the science of tax law, since one of the main purposes of taxation is to replenish the state budget. In the process of developing public relations and the taxation system, the regulatory component of taxation was also developed, which was used by the state, including for economic development. The author concludes that the fiscal and regulatory functions of a tax are equivalent. The methodological base consists of general scientific research methods such as analysis and synthesis, deduction and induction, generalization, description. Along with general scientific methods, the author also used special legal methods, such as formal legal (dogmatic) and comparative legal methods. The novelty of the work is due to the allocation of sub-functions of the regulatory function of the tax within the framework of a multifunctional approach. A study of various classifications of tax functions has been conducted, and therefore a conclusion has been drawn about the polyfunctionality of the tax, as well as the need to identify the following sub-functions of the regulatory function of the tax: stimulating, distimulating, encouraging, auxiliary. Thus, the regulatory function of the tax is the most important function for creating a favorable economic, investment and social climate in the state, and the tax, along with the fiscal function, can perform additional functions. With its help, the state can stimulate the development of priority areas of entrepreneurial activity, influence demographic policy and other socially important processes, as well as restrain the development of certain business areas, which affects other areas of social life.