Introduction. Due to the full-scale war between Ukraine and the Russian Federation, there is a sharp deterioration in absolutely all macroeconomic indicators, such as GDP, inflation, unemployment and so on. In the conditions of war, the formation of state revenues and expenditures depends on the effectiveness of tax policy to enable Ukraine to perform its state functions. Taxes play a dominant role in revenues and expenditures, so the implementation of effective tax policy of Ukraine is an extremely important issue and becomes especially relevant in the context of the importance of its impact on all spheres of public life and ensuring the functioning of the country. Goal. The purpose of the article is to improve tax policy to ensure the security of Ukraine both nationally and internationally. Method (methodology). In the course of the research the following methods were used: dialectical, generalization, comparison, system analysis, observation of economic activity, graphic, etc. Results. It is proved that the financial and economic front is becoming no less important than the real military one, because without it is impossible to effectively defend Ukraine at the domestic and international levels. It is substantiated that the main problems of tax policy before the invasion of the Russian Federation were: complexity and inconsistencies, frequent and numerous changes in tax legislation, excessive and uneven tax burden on taxpayers, which did not stimulate business and other activities, but contributed to tax evasion, budgets of different levels, large-scale shadowing of the economy, slow harmonization and unification of domestic legislation to EU requirements, etc. It has been proved that it is necessary to build such a tax policy that would make it possible to meet at least the basic needs of the state, support entrepreneurship and a sufficient standard of living, and so on. It is substantiated that it is necessary to prevent further stagnation of Ukraine's economy. Measures for the effective application of security measures and measures to improve tax policy in the context of hostilities are proposed.