A study has pointed out that social networking sites are being blamed for the poor performance of students.
According to a report, children who spend much of their time online find it harder to concentrate in class, are permanently distracted and have shorter attention spans.
Teachers also put the dip in the quality of children's homework down to their willingness to spend their evenings on Facebook and Twitter instead of studying.
And many are unhappy at the increase in the number of children who are using text-speak or social networking chat - such as 2mor, msg, lol and bk - in place of English grammar.
The worrying stats emerged in a study of 500 teachers conducted by leading school trips provider JCA - which motivates personal and social development outside the classroom.
"This research clearly demonstrates that students up and down the country are spending more and more time using social media," the Daily Mail quoted a spokeswoman for JCA Janie Burt as saying.
"Rather than relying on life experiences, educational travel and face to face interaction with others, children are becoming obsessed with social networking and this is shaping their attitudes instead.
"And as the teachers spell out, it is this obsession which has a direct impact on the future of our children - affecting their grades because they fail to complete their homework on time or to the standard required, and being unable to concentrate in class," Burt added.