Teachers have caught children as young as seven sexting with more than half of those surveyed reported that pupils are using social media to share sexual messages and pictures.
The survey by teaching union NASUWT revealed 63% of teachers surveyed said they were aware of 14-year-olds sexting, while 45% said those involved were aged 13.
A handful of teachers said pupils aged seven, eight, and nine sent messages of a sexual nature.
More than half of those quizzed said they were aware of pupils using social media to bully their peers or send messages of a sexist or racist nature.
The "devastating" impact of social media on the classroom is also affecting teachers, the survey revealed.
Half of those surveyed revealed that they had discovered negative or abusive comments about them online from both pupils and parents including being falsely called a paedophile and receiving rape threats.
Others complained of doctored images of themselves being shared on social media including one to make them look like Islamic State ringleader Jihadi John.
Almost one-third (31%) saw a photo or video of them taken without consent, while almost one-tenth (9%) experienced threatening behaviour.
Chris Keates, general secretary of NASUWT, said that the survey has been running for three years and the situation has deteriorated.
Examples of offensive comments from pupils, and parents, shared online include:
- A fake Twitter account set up by pupils describing the teacher as a wife beater
- A song posted by pupils which suggested their teacher had an affair at school
- A Facebook group set up by pupils specifically to mock the teacher's appearance
- Multiple threats from parents to "knock out" or "sort out" the teacher
- A comment that the teacher was "unsuitable to work with children and deserved the sack", engaging in a campaign with other parents to try to make it happen.
Some 60% of NASUWT members surveys said that pupils had used Facebook to get in contact with them and 15% had received a message from Twitter from a student.
One-third of teachers said they did not report the personal abuse, with half of them saying they feared nothing could be done.
A spokesperson for the Department of Education urged teachers to report online abuse and threats.