The work analyzes the role of tax debt in the formation of the shadow economy and its impact on the national economy. The amount of tax debt and its impact on the economic development of the country is considered. The relationship between the shadow economy, in which tax debt is one of the key elements, and the general state of the economy is investigated. The work highlights strategies and tools that can be used to reduce tax debt and its negative impact on the national economy. Proposed proposals for improving the tax policy and improving the control system aimed at reducing the scale of the shadow economy and improving the country's financial stability. The study reveals the key factors that contribute to tax losses from the shadow economy, and based on this, an analytical table for 2015–2021 was created, and the specific weight of tax debt and the shadow economy in the national economy of Ukraine was additionally calculated. The article schematically plots the growth of tax losses over the analyzed period, both from the shadow economy separately, and from tax debt and the shadow economy in general. The analysis shows that these losses exceed almost half of the actual tax revenues received by the Consolidated Budget of Ukraine. The existence of a shadow economy and tax debt leads to significant losses for the state, which should be a source of additional income for the economy, necessary for the effective financing of various budget expenditures. Tax debt and the shadow economy are becoming tools used by taxpayers for illegal tax evasion. The study also highlights the consequences of tax debt and the shadow economy for the national economy, including the limitation of financial resources for social and infrastructure projects. Recommendations are offered to improve the effectiveness of tax policy and reduce the risks of the shadow economy and the amount of tax debt. The obtained results can be used to develop recommendations for improving tax policy, aimed at reducing tax debt and activating economic activity in legal channels. The research is relevant and useful for authorities, tax services, and scientists who are interested in improving the efficiency of tax administration and reducing the shadow economy. Also, the research is important for understanding the problem of tax debt as a component of the shadow economy and can serve as a basis for developing strategies to overcome this phenomenon in order to increase the financial stability of the state budget.