The main result of the study is a systematic analysis of the peculiarities of legal and political institutionalization of public associations in Ukraine, ways of increasing the effectiveness of regulation of the activities of public associations in Ukraine by means of institutional support, institutional capacity of which is the result of their interaction with the state. This is manifested in the ability of public associations to perform their functions in providing social services in areas that are legally and normatively defined by the state. The evaluation of the effectiveness of relations between civil society actors, the form of institutional support for the activities of associations of children and young people on a public-legal basis, necessary for the effective use of the... potential of different types of public associations, as well as optimal ways to increase the effectiveness of institutional support for public associations in implemented youth and social projects. The institutionalization of the process of interaction of public authorities with public organizations and their associations is highlighted in the context of consolidation of the organizational and legal rules of their relations, the conditions of their partnership cooperation in various spheres of socio-political and socio-economic life of the country. Institutionalization is revealed as the legitimization of the foundations of the interaction of these institutions, that is, the recognition of their interaction is legitimate and expedient for the majority of the population, whose interests are the institutions of civil society. The forms of institutional support for the activities of associations of children and youth are presented, which directly determine institutional support instruments, which can be either direct or indirect.The presented results of the conducted research testify to the necessity of further development of civil society on the basis of cooperation between state authorities and the public. An indispensable condition for such interaction is the formation of an appropriate mechanism of public administration, in which a system of social and legal norms, methods for defining purposes and a legal basis for the management process in this direction are identified. The prospects for further research in this direction are envisaged, which include the development of proposals for improving the structure of state bodies - elements of the system for ensuring interaction between authorities and the public, improving the coordination of their activities.