The purpose of the article was to analyze the international forms of legal regulation of corporate relations and their consequent transformation in the corporate law of the European Union EU and Ukraine. The methods of this research were: monographic analysis, analysis and synthesis, systematic, comparative and legal, prospective and generalization. The formation and development of the EU corporate legislation is analyzed. A comparative analysis of the EU and Ukrainian corporate legislation in its different stages and forms of adaptation in accordance with the EU legislation is also carried out. It is concluded that modern EU corporate legislation is the result of the historical development of EU law in general and, its transformation into a specific, independent legal system. It is emphasized that company law in the EU is increasingly subject to unification, and with the adoption of the European Company Acts, the company law of the EU member states is also subject to constant transformation. Ukraine, as a candidate to join the EU, should implement measures aimed at adapting and unifying its corporate legislation to EU laws.