- 2 updates
Claire Lilley, policy adviser at the NSPCC, said she hoped the findings would ring "alarm bells" with authorities that the problem required urgent action.
The NSPCC obtained the statistics through Freedom of Information requests to each of the 43 police forces in England and Wales.
But only 34 forces supplied figures - revealing a total of 5,028 offences - so the true number of offences is likely to be higher, the NSPCC said.
Thousands of young people are committing acts of sexual abuse against other children every year, a charity warned.
The NSPCC found there were more than 5,000 cases of abuse by under 18s reported to the police in the last three years.
In some instances acts of sexual abuse were committed by children as young as five or six.
Nearly all (98%) of the 4,562 offenders were boys and where the relationship was recorded, at least three out of five of the victims knew their abuser, the NSPCC said.
More than a third of the offences were said to have been committed by a family friend or acquaintance, and one in five by family members.