The European Union is an intergovernmental and supranational organization of 27 European countries. Enlargement is considered one of the most important tools of the European Union, because by joining the European Union, states become modern and functional democracies. The last country to join the European Union is the Republic of Croatia, which after a long process, on 1 July 2013 became a full member of the European Union. The Republic of Croatia has gained membership in the European Union with the possibility of equal participation in the single European market, free movement of goods, services, labor and capital, easier access to companies in the European market, access to some new knowledge and technology, as well as structural and cohesion funds. a whole range of benefits, and that is the goal of the European Union. In this paper, we get acquainted with the history, goals, institutions, activities and members of the European Union, as well as with the entire path of the Republic of Croatia towards membership in the European Union.