This article aims to examine the main approaches of the concept of civil society institutions. As the research of the concept differs through evolution, content and characteristics, the analysis will be focused on both foreign and Moldovan literature. Thus, there will be analysed the main terms: civil society, nongovernmental organizations, non-profit sector, non-commercial organizations, public associations and civil society organizations from the point of historical evolution which eventually contributed to creating a clearer picture of the concept of civil society institutions.