London's mayor Ken Livingstone and a gay rights charity are launching a campaign to tackle homophobic bullying in schools.
Homophobic bullying can be difficult for teachers to handle
They will urge education authorities to be more aware of bullying in the classroom and have produced a DVD to help teachers.
A conference will be held in London on Tuesday on the issue.
Stonewall spokesman Alan Wardle said homophobic bullying was sometimes difficult for teachers to tackle.
'Invisible and ignored'
The DVD has been produced by Stonewall and the Greater London Authority to introduce teachers to the subject.
Mr Wardle said: "Ofsted said a couple of years ago that homophobic bullying is one of the most difficult to tackle and quite often it's being ignored and [is] invisible.
"What we are doing is raising awareness of the issue.
"Hopefully this resource will help schools to tackle that and give teachers more confidence."
The conference will also look at practical ideas about school curriculum and how to challenge bullying and offensive language in the classroom.
The Department for Education and Skills has said it is working to ensure that schools provide anti-bullying training and materials for teachers.