The aim of the thesis is to analyze tax evasion in the Republic of Croatia. After the introductory considerations, the second chapter focuses on the gray economy, due to its very close connection with tax evasion. The definition of the concept of the gray economy is given, the causes of its origin and its manifestations are explained, and the positive and negative consequences for the economy are stated. Then, measures to prevent the gray economy are presented, and the chapter ends with an assessment of the size of the gray economy in the Republic of Croatia. The third chapter focuses on the issue of taxation in the Republic of Croatia. In the third chapter it is also explained what taxes are, what types of taxes and tax forms there are, what role taxes play in financing public needs, and the development of the tax system of the Republic of Croatia is also presented. In the fourth, also the main chapter of the thesis, tax evasion in the Republic of Croatia is analyzed. After explaining the basic concepts, the legal framework of tax evasion in the Republic of Croatia is presented, the forms of tax evasion and the measures for its prevention are also analyzed. The last chapter of the paper presents concluding considerations.