Object: the process of formation of social activity of youth. The purpose of the study: to theoretically substantiate and experimentally test the system of formation of social activity of youth in civil society institutions. In the thesis theoretical foundations of studying youth social activity are presented; methodological approaches to the process of developing youth social activity at civil society institutions are considered; the results of empirical research of implementing the system of developing youth social activity at civil society institutions are represented. It is defined that modern scientific approaches to determining social activity are based on the position of personal contentment, way of action, and orientation to the environment. In the line of studying the issues of developing youth social activity, the social activity is defined as an integrated personal activity that concerns initiating and implementing socially-oriented actions within their own civil and political awareness, taking into account personal social competence, self-assessment, and modern requirements of the society. The structure of youth social activity is defined as a unity of motivational and value-based, content-cognitive, social and activity-based, and reflexive-evaluative components. Based on the methodological approaches to the process of developing youth social activity at civil society institutions, it is defined that the process of developing youth social activity includes the implementation of some methods in accordance with the activity areas of certain civil society institutions: project activities, civil and political activities, volunteer and charitable activities, educational and scientific activities, youth policy, and leisure activities. The conceptual principles of developing youth social activity at civil social institutions are distinguished; the system-based approach is considered to be the theoretical basis of the research of developing social activity; it is defined that the process of forming and developing youth social activity depends on the level of youth participation in the activities of civil organizations, charitable foundations, youth councils, and youth centers; the technology of developing youth social activity, using of various forms and methods of work with youth at civil society organizations, is presented. The system of developing youth social activity at civil society institutions is modeled as a holistic process that includes a set of interconnected and interdependent components, which are a purpose, an object, a subject, content, directions, forms, and methods of work with youth at the civil society institutions. The thesis presents the experimental research on implementing the system of developing youth social activity at civil society institutions and analysis of its effectiveness. The quantitative and qualitative analysis of results of diagnosing experimental and control group before and after conducting forming experiment shows the sustainable improvement of the level of the development of youth social activity in the experimental group that proves the effectiveness of the proposed system of developing youth social activity at civil society institutions.
