Tewkesbury School in Gloucestershire has installed new software designed to detect cyberbullying and to search for inappropriate words and phrases.
The technology and language college hopes the new kit will protect its pupils from internet predators.
The system also monitors pupils working offline and provides screen shots of every violation along with details of the user, workstation, time and date.
It can also see pupils who illegally download and share unlicensed files.
'Acceptable use policy'
Headteacher John Reilly said: "We are delighted to have found a product which enables us to reassure staff, students and parents that computer usage at Tewkesbury School is safe and secure."
Bill Jenkins who founded Securus said the software monitored pupils' use of the computer and internet.
Pupils have to agree to an acceptable use policy set by the school when they log-on to their computer.
"The pupils know their computer use is being logged. If someone sends an inappropriate e-mail for example, this is flagged and an electronic snapshot taken.
"This automatic monitoring means the children don't have to be the whistle-blower.
"Schools tell us when pupils are using chatrooms they are always quick to point out to people at the other end they are being monitored because they risk being denied access if inappropriate messages are being exchanged."