The purpose of this research was to examine whether loneliness might play a mediating role between perceived social competence and cyberbullying in Turkish adolescents. The participants were 326 high school students who completed a questionnaire package that included the Cyberbullying Scale, the Perceived Social Competence Scale, and the UCLA Loneliness Scale. Relationships between loneliness, social competence and cyberbullying were tested using Pearson Product Moment Correlation Coefficient and predictions of each variable by the domains of the other were calculated with Linear Regression Analysis (LRA). Findings showed that perceived social competence, cyberbullying and self-efficacy were related to each other's. Hierarchical Regression Analysis results indicated that loneliness partially mediated the relationship between perceived social competence and school burnout.