The purpose of this research is; to examine the relationship of cyberbullying and victimization among adolescents with the self-concept and peer relationships, which is important developmentally in this period. The sample of the study consisted of 879 adolescents between the ages of 14 and 17. Simple random sampling method was used in sample selection. The research was carried out in relational screening model. Within the scope of the research, Piers-Harris Children's Self-Concept Scale, Peer Relationships Scale and Revised Cyberbullying Inventory were used as data collection tools. Pearson Coefficient of Correlation and Hierarchical Multiple Regression Analysis were used in data analysis. As a result of the research, it was seen that cyberbullying and victimization increase as adolescents' general self-concept decreases. The dimensions of self-concept, `behavior and compliance' and 'happiness and satisfaction' are determined as the prominent variables in this relationship. While there is no meaningful relationship between general peer relationships and cyberbullying and victimization; cyberbullying and victimization have increased as loyalty in peer relationships increases. The results of the research reveal a high level of positive relationship between cyber victimization and bullying. Results were discussed and recommendations were given in the light of the literature.