Despite the significant number of research in the field of relations psychology, the problem of interpersonal relationships disharmony remains insufficiently explored both in theoretical and practical terms. Internet addiction is an important issue in disharmony development of interpersonal relations between teenagers. Analysis of the social situation shows that the majority of teenagers meet their needs in communication on the Internet, which leads to difficulties in real interpersonal interaction. The paper defines the concept of “disharmony of interpersonal relations” and its indicators. Adolescence is characterized as a sensitive period in the development of interpersonal relations where the most valuable aspect is the relationship with peers. It is emphasized that sustained presence on the Internet contributes to the emergence of alienation, tension, conflict, aggression in the process of interpersonal interaction, emotional closeness, and distortion in the perception of social reality. An empirical study has been performed on a sample of 50 adolescents using two methods: a questionnaire “Subjective evaluation of interpersonal relations” (the author S.V. Dukhnovsky) and a test for Internet addiction (K. Young, adapted by V.A. Burovaya). The paper presents the results of the study of interpersonal relationships disharmony characteristics of teenagers with different levels of Internet addiction. According to the results of the study, there is a statistically significant difference in disharmony characteristics of interpersonal relations between adolescents with low, medium and high levels of Internet addiction upon such indicators as alienation, tension, conflict, and aggression in relations. The data obtained through the study allow us to make a conclusion about the features of disharmony in interpersonal relations of adolescents with different levels of Internet addiction and can serve as a basis for improvement of the interpersonal relations in adolescence.