Cyberbullying is an emerging threat to children in Europe. However, European research into this topic is scant and knowledge of it incomplete. In this study, “cyberbullying” involves the use of different technological platforms to support hostile behavior by an individual or group that harm others. The article examines whether children's experience of cyberbullying differs according to technological platforms and socio-demographic variables. Results from two Norwegian studies show that cyberbullying most often occurs via e-mail, and that girls and frequent users of the internet are more likely to encounter cyberbullying. Most cyberbullying encountered in social networking sites was sexual and took place in communities in which the users are anonymous. This was most often encountered by teenage girls and perpetrated by adults.