The content of this article includes the synthesis of the reference studies of international authors. It discusses, mostly, on the basis of different approaches to the concept of security from the perspective of representatives of Realism, Liberalism, Functionalism and Constructivism within International Relations theory. This brief analysis allows to enter the essence of each of these doctrines and its various interpretations. The security concept sees a dynamic development of its treatment within International Relations theory, diversifying into new lines of today modern research.