The right to freedom of association is one of the fundamental human rights guaranteed by both, the most important international treaties and the national laws of the Republic of Croatia and other European states. This human right represents the basis for voluntary association of citizens with the purpose of achieving and fulfilling various goals and tasks. One of the most important and most common organizational forms whereby citizens exercise the right to freedom of association are associations. As means to realize the freedom of association, associations enjoy certain autonomy. However, the autonomy of associations is far from absolute; it is limited not only by enforcing the supervision in the course of its founding, operation and dissolution, but also by ensuring that the association and its members are responsible for the violations established by the competent authorities and that the members are protected from illegal acts of the association. Generally, the supervision of legal persons that pursue private goals and interests is identified by special regulatory features whose main purpose is to establish strict compliance with the prescribed rules. This is of particular relevance to associations, the most numerous non-profit organizations, which on the one hand guarantee freedom of association, and on the other hand facilitate protection of the public interest and the interest of third parties from the illegal acts of associations. However, certain provisions concerning the supervision over associations in Croatian law, together with Croatian case law, are not consistent with European legal instruments or laws of the analyzed European states. This primarily refers to the inadequacies in the laws which regulate the implementation of preventive supervision, i.e., supervision carried out at the founding of an association. The inadequacy further relates to the implementation of subsequent supervision, which is carried out after the association has been founded and when it has already commenced its activities, namely the rules concerning the bodies governing the association and supervision of their operation, supervisory mechanisms for the protection of members of the association, supervision over the activities of associations and responsibility of members of the association for violations established by the supervisory authorities. Therefore, the aim of this doctoral dissertation is to contribute to understanding open issues related to the legal regulation of supervision of associations and improving the legal framework for associations in the Republic of Croatia, by means of a comprehensive analysis of the current legislation and case law in the Republic of Croatia and by existing legal solutions in comparative law.