Introduction. The socio-economic and political processes that have taken place in recent decades in Ukraine have led to a rethinking of the importance of many, both individual and social values, changes in social stereotypes and interpersonal interaction. Assertiveness, as the willingness of the individual to assert his own position, even when it contradicts the position of the majority, is now of particular importance in a society with a considerable arsenal of means of pressure, manipulation and subjugation of the will of the individual. Against this background, the willingness and ability to defend one's position and act independently of the majority opinion can be fatal for both the individual and society as a whole. Thus, the problem of assertiveness, assertive behavior in modern society is becoming especially relevant in both social and scientific aspects.Purpose. To clarify the essence and psychological features of the phenomenon of assertiveness in modern society.Methods. Analysis, generalization, systematization of scientific materials, subordinated to the task of identifying the basic methodological approaches and theoretical and empirical study of assertiveness in order to conceptualize this phenomenon.Originality. The article deals with the nature and psychological features of the phenomenon of assertiveness. The idea of assertiveness as a practical methodological theory of interpersonal interaction is clarified. The principles and criteria of assertive behavior are presented. The problem of assertiveness in modern society is considered.Conclusion. Assertiveness is of particular importance in society. The problem of assertiveness in contemporary society is becoming especially relevant in both social and scientific aspects. Assertiveness is an important determinant of personality development and contributes to the disclosure of one's psychological potential. It influences the development of effective communication, activity, responsibility, social courage in advancing and meeting new goals and objectives. In the light of the above, the study of assertiveness at the present stage of society's development is of considerable interest and needs further theoretical and practical scientific generalizations.