How others behave (descriptive norm) and what they expect from us (injunctive norm) has a strong influence on how we behave. However, children and adolescents often overestimate the prevalence of negative behavior among their peers. The current study tested whether prompting peer norms for cyberbullying may foster anti-cyberbullying norms in an experimental design with N= 510 seventh, eighth and nine graders. In a pre-post control-group design, students completed an online survey during school lessons assessing the individual and classroom anti-cyberbullying norm before and after receiving simulated information about the classroom norm on cyberbullying. Results showed that individual anti-cyberbullying norms are negatively related to cyberbullying behavior. However, students did not change their individual norm differentially after reading the information about the classroom anti-cyberbullying norm. Possibly, the intervention was too minimal to change normative attitudes about cyberbullying or the school class is not a relevant reference group for online behavior of students.