The theme of this thesis is the European Environmental Policy; environmental policy that is taking place in the 21st century significantly affects the environment itself and seeks to preserve the environment better in its natural form through an effort to reduce pollution to the environment and the very quality of life of people on Earth. This thesis consists of fifteen chapters in which I have dealt with certain areas of European Environmental Policy, how European institutions, agencies and other non-governmental organizations influence the environment itself and try to protect the environment in a better, efficient and more transparent way. In the first two chapters I have dealt with the theoretical part of European environmental policy, its emergence and development in Europe, the legal basis and principles of the European Union in environmental protection, and its institutions, non-governmental organizations and agencies that have an impact on the European Union's environmental policy. The future and contemporary development of the European environmental policy has a significant impact on the development of the environment that has been addressed in this thesis. In the last chapters of the thesis, I have elaborated the theoretical part of the environmental protection policy in the Republic of Croatia as a member of the European Union and its institutions regarding environmental protection and financing and the goals of environmental policy development in the Republic of Croatia.