Cyberbullying is usually operationalised as a kind of bullying understood as peer aggression that is intentional and continuous, and involves an aspect of imbalance of power between a victim and a perpetrator or perpetrators. Despite the tool used (new media), cyberbullying often takes place within a traditional group (e.g. school class). However, cyberspace gives Internet users the opportunity to attack other individuals: people known only from the Internet, celebrities, teachers, totally unknown individuals or whole groups of people. Involvement in such actions brings suffering to those victimised as well as potential negative consequences for the perpetrators. This article presents a typology of electronic aggression based on qualitative research data (interviews with teachers and students). The typology was validated in a large quantitative survey on a representative sample of Polish 15-year-olds. The survey gives the prevalence of perpetration of different kinds of electronic aggression, as well as some influencing factors (e.g. gender) and risk and protective factors (attitudes towards school, peer norms, negative relations in the family, norms concerning online behaviour at school/home, pro-aggressive beliefs, level of self-esteem). The need to broaden prevention and intervention measures, and not restrict them to the issue of electronic peer aggression, is discussed. (Contains 3 tables.)