A freedom of information request by Press Association to 15 local authorities found there were 754 reported incidents between July 2013 and April 2017.
There were at least 40 incidents of children below 10 years old, the age of criminal responsibility, disciplined for misdemeanours.
Schools said children could be censured under the term "sexual misconduct" for a range of issues, including sexual abuse, assault, bullying, graffiti and harassment, as well as lewd behaviour.
Maggie Ellis, head of Lifecentre, a Christian national rape crisis charity told Premier kids acting out sexually is a sign things are not right at home.
She said: "They have been exposed to sex already. That child has suffered some form of abuse, whether it's direct sexual abuse or inappropriately been exposed to pornography, or been exposed to adults being sexual.
"Those children need to not be excluded, they need to be helped. What we need is social workers and child counsellors to get alongside them, and out what is it that they are copying."
Ellis added that the child needs to be taught healthy boundaries and healthy socialising in regards to how they behave physically and sexually.
The vast majority of exclusions were on a fixed-term basis, with 14-year-olds the most likely to be involved in sexual misconduct.
An NSPCC spokesman said: "Social media, sexting, online porn and dating apps did not exist when sex education was introduced on the curriculum a generation ago.
"It must be dragged into the 21st century, it must be consistent, and it must be offered in every school as part of a broader PSHE (personal, social, health and economic education) curriculum."
While Ellis agreed that schools have a responsibility to teach up to sat sexual education, she advised the Church to also do its part in protecting children from inappropriate sexual behaviour.
She said: "I think our roles of churches is to be salt and light in society and that means in a positive way, not in a critical way, getting involved in our schools, making sure that the schools are profiling to the parents how to put really strong filters on all computers and monitor access to the internet by mobile phones etc.
"Parents from churches should go and talk to the head teachers and pastoral staff and find out what is happening and encourage them to protect children in that way. "
Churches' Child Protection Advisory Service (CCPAS) called the figures highly concerning.
Karen Eakins, Head of Training Consultancy at the charity told Premier: "Part of the reasons for this trend, is the lack of positive input to children and young people on the values and characteristics of a healthy relationship."
"At CCPAS we feel the church very much has a role to play here, in promoting healthy relationships, and in creating safe places where children and young people can talk about their concerns. The church can be a healthy place where children and young people can be exposed to positive role models."
"We believe there is an opportunity for churches to not shy away from speaking about the importance of healthy relationships and tackling some of the big issues such as domestic abuse and sexual exploitation in an appropriate and constructive way."
Listen to Maggie Ellis speaking with Premier's Tola Mbakwe here:
