Although bullying and relational aggression among students are longtime concerns, the elusive nature of cyberbullying compounds the difficulty of identifying harmful behavior and intervening to stop it. Principals across the country are struggling to determine their authority over cyberbullying that technically may occur outside of school but for which the effects on students in school are very real. Cyberbullying can undermine school climate, interfere with victims' school functioning, and put some students at risk for serious mental health and safety problems. School leaders cannot ignore cyberbullying but rather must understand its legal and psychological ramifications. In this article, the authors talks about cyberbullying, cyberbullies and victims, the consequences of cyberbullying, and what schools can do to prevent and respond more effectively to cyberbullying.