The topic of protest gatherings is intrinsically present in the social context. From the beginning of the first tribes until today, it has reflected man's inherent need for association, gathering and expression of disagreement. In the modern era, the concept of protest gatherings is becoming ubiquitous, but paradoxically, it is still insufficiently treated in detail. This paper systematically investigates the legal aspects of protest gatherings in the Republic of Croatia and the European Union, analyzing the very concept of protest gatherings and the accompanying legal norms. Through an overview of relevant laws and by-laws, we will consider how this specific area is regulated, arguing the right to assembly as a fundamental human right, the inviolability of which is protected by the Constitution of the Republic of Croatia as the highest legal act, the European Convention on Fundamental Human Rights and Freedoms, and a number of other acts. The thesis additionally integrates the results of the research of real examples, including the practice of Croatian courts, and analyzing the practice of the European Court of Human Rights.