Abstract The article is devoted to a comparative analysis of the tax systems and accounting practices in the USA and the European Union (EU) countries. It examines differences and similarities in tax structures, accounting approaches, and their impact on the economy and business environment. The influence of tax policies and accounting standards on international companies, their choice of jurisdiction, and the adaptation of business processes are analyzed. Special attention is given to aspects such as the decentralization of tax systems and the standardization of accounting practices. The article discusses the application of International Financial Reporting Standards (IFRS) in the EU and Generally Accepted Accounting Principles (GAAP) in the USA, as well as their impact on the financial reporting of multinational corporations.