The government has launched a new awareness campaign to draw attention to cyberbullying.
Ministers are increasingly aware of children using mobile phones and internet sites to bully other pupils and teachers, with government research suggesting one in three teenagers have been victims of cyberbullying.
Guidelines issued today are designed to help schools adapt to these new opportunities for bullying and malicious behaviour.
Schools and pupils will be given advice on how they can tackle cyberbullying, including why not to respond to malicious texts and emails, the importance of saving evidence to report bullying and how to keep passwords and mobile phone numbers private.
A £200,000 campaign, to run on social networking sites such as Facebook and MySpace, will raise awareness of cyber-bullying.
Laugh At It and You're Part of It wants to spread the message that watching or passing on so-called "happy slapping" videos of abuse can be just as bad doing the bullying first-hand.
Schools secretary Ed Balls said cyberbullying is distinct from normal bullying, partly because bystanders can easily become perpetrators by spreading viral material.
Mr Balls said: "Cyberbullying is a particularly insidious type of bullying as it can follow young people wherever they go and the anonymity that it seemingly affords to the perpetrator can make it even more stressful for the victim.
"Cyberbullying takes different forms: threats; intimidation; harassment or 'cyber-stalking'; unauthorised publication of private information or images; impersonation; and 'happy slapping'.
"Bullying evolves as society and technology changes, so schools need to get to grips with newer forms of bullying and the different impact these have on the victim."
Anti-bullying groups, who helped draw up today's guidance, told ministers cyber-bullying is particularly harmful because it extends beyond the school gates, with victims potentially subject to abuse 24-hours a day.
NASUWT said the guidance was to be warmly welcomed but more urgent action was required.
Chris Keates, NASUWT general secretary said: "Unfortunately, as good as the government's guidance undoubtedly is there is still more that needs to be done.
"At present the guidance relies on industry self-regulation as a key strategy for preventing abuse. This is unlikely to work. More and urgent action is required."
Dr Mary Bousted, of the Association of Teachers and Lecturers, added: "The government's guidance should help save pupils from future bullying, but we now need to see the same support for staff.
"All schools and colleges should have policies to protect their teachers and support staff from cyber bullying, and should make a commitment to fully support anyone who is a victim."