Web giants like YouTube are being urged to get tough with the cyber-bullies that use their sites to make pupils' and teachers' lives a misery.
The education secretary will say web providers have a "moral obligation" to cut offensive videos of people being attacked, harassed or ridiculed.
Bullying is causing many teachers to leave the profession, Alan Johnson will tell the NASUWT conference in Belfast.
Advice to tackle anti-social behaviour in schools is due to be published.
'Cruel and relentless'
Mr Johnson will also point to new powers teachers have to confiscate mobile phones and MP3 players used for such abuse.
He will tell delegates at the teaching union conference: "Cyber bullying is cruel and relentless, able to follow a child beyond the school gates and into their homes.
"The online harassment of teachers is causing some to consider leaving the profession because of the defamation and humiliation they are forced to suffer."
He will urge the providers of websites like YouTube and Rate My Teachers to "take firmer action to block or remove offensive school videos in the same way that they have commendably cut pornographic content".
He will add: "By removing the platform, we'll blunt the appeal."
Web providers, many of whom the government works with on its cyber-bullying task force, have a "wider responsibility" to consider the harm that offensive like videos of teachers or pupils often filmed on mobile phones can cause, he will add.
"These are big companies we are talking about: they have a social responsibility and a moral obligation to act."
Teachers have been calling for tougher restrictions to be put in place to prevent them being targeted by online bullies.
They claim offensive videos of them being abused, bullied and derided by pupils affect their ability to command respect in the classroom and causes them pain.
RateMyTeachers website insists that it does read and moderate its content and argues 70% of its postings are positive.
YouTube's website says it trusts its users to "be responsible, and millions of users respect that trust".