The objective of this paper is to try to identify the specificity and frequency of cyber-agression as a form of problem behaviour characteristic for the contemporary youth known as Generation Y. Analysis of the results of research conducted among schoolchildren aged 15–16 indicates that cyber-agression is a common phenomenon in the group. It raises the need for reconstruction and re-evaluation of practices and standards developed to date and implemented to address the problematic behaviour of young people through the global network. (...) In the paper, proposals for solutions in this area are presented, which can be used to create future prevention programs aimed at constructive online behaviour and foster rational choice-making regarding the use of the Internet and modern media. (shrink)