Although peer victimization is of major concern and adolescents spend increasing amounts of time on the Internet, relatively little is known about the psychosocial antecedents and consequences of online victimization. The main aim of this study was to compare the psychosocial antecedents and consequences of online versus real-life victimization. More specifically, the bidirectional relationship between online and real-life victimization on the one hand and psychosocial problems (i.e., loneliness and social anxiety) on the other was examined. In addition, the moderating role of online aggression in the relationship between online victimization and subsequent psychosocial problems was studied. This prospective study, consisting of three annual measurements, was conducted among a sample of 831 adolescents (50.3 percent girls) aged 11-15, of which most (80.2 percent) had a Dutch ethnic background. The results indicate a unidirectional relationship whereby loneliness and social anxiety predict an increase in latter online victimization rather than the reverse. A bidirectional relationship was found for real-life victimization: loneliness (but not social anxiety) predicted an increase in latter real-life victimization, which in turn predicted an increase in subsequent social anxiety (but not loneliness). No moderating effects of online aggression were found. The findings of the present study suggest that negative online and in real life peer interactions have a differential meaning for, and impact on adolescents' well-being. Abstract published by arrangement with Springer.