Introduction. The development of the taxation theory and the best practices of the World Anti-crisis Tax Policy prove the gradual separation of an independent and very specific group of taxes, called “solidarity taxes”, which are beginning to play a fairly significant role in modern tax policy. The intensive development of solidarity taxes and their implementation in the European fiscal space in 2022 are closely related to the crisis phenomena that have arisen in the field of energy prices and the associated increase in the inflation rate. This is one of the consequences of the military aggression of the Russian Federation against Ukraine. Another consequence of this war was the high need for investment necessary for the revival of Ukraine. Problem Statement. The problems of the design of solidarity taxes and their scope of application, as well as the possibilities and features of their use as a promising source of investment financing, remain insufficiently studied. And the latest experience of the second half of 2022-early 2023 regarding the coordinated application of taxes on unpredictable profits in EU countries requires critical analysis and generalization. Purpose. To study the economic content, evolution and regulatory framework of the application of solidarity taxes in the EU and the prospects for their implementation in Ukraine at the stage of post-war economic recovery. Methods. The author used analytical and qualitative research methods, including logical and comparative analysis, to identify general and special features of solidarity taxes, decomposition and grouping methods to study the element base and identify models of the studied taxes. Results. The theoretical basis and European practice of using solidarity taxes are analyzed, and the genesis of their development in the EU countries is studied. The principles of development and implementation of a common tax policy within the EU to counteract the consequences of the energy crisis through the introduction of a temporary contribution of solidarity, coping with unexpected profits in the energy sector and oil refining are considered. Attention is focused on the expediency, limitations and risks of the prospective application of solidarity taxes as its own source of investment financing at the stage of the post-war economic recovery of Ukraine. Conclusions. Solidarity taxes implementation is a promising direction for creating our own national sources of investment financing in the context of the post-war economic recovery. The introduction of solidarity taxes in Ukraine requires the adaptation of the European methodology to the specifics of the set goals and conditions of taxation in Ukraine, as well as scientific justification of restrictions on the application of this tax and preventive mechanisms to counteract the negative consequences of its implementation.