More and more kids are being targeted by bullies who use technology like emails, websites and text messages.
The news comes in the same week that newspapers reported a 13-year-old was being bullied by two school boys who set up a website to attack him.
A four-year survey of more than 11,000 children found nearly 15% had received nasty or aggressive messages.
Researchers have seen a steady increase in the number of children suffering from cyber bullying.
It was found that girls were more likely than boys to report being bullied by email and text messages.
Researcher Nathalie Noret said: "Teachers and parents need to realise that a child's mobile phone or computer isn't just a communications tool - it is also a way for a bully to reach children in their own home."
The boys who set up the website, which was live for several months, were suspended from school but have now returned. They received formal police warnings.
The boy they bullied has moved to another school.