Young people are more worried about exams than they are about bullying, relationships or problems with parents, according to a study by the National Society for the Prevention of Cruelty to Children.
A third of 11 to 16-year-olds are in a state of constant anxiety, says the society. Concerns about exams and homework are top of the list of children's wories.
The society found that one in nine children describes themselves as "extremely worried".
"In every classroom there are likely to be up to four children who hate leaving the house in the morning because of problems at school," says the NSPCC.
More than eight in 10 (82 per cent) say they worry about examinations and almost three-quarters (73 per cent) think they have too much homework.
Around half worry about bullying or problems with teachers.
The findings are based on a representative survey of 750 11 to 16-year-olds carried out by the society last November.
They are published in a report, called Someone to turn to? which takes the name of a new NSPCC campaign aimed at encouraging young people to talk about abuse and other worries.
The report offers fresh ammunition to those who argue that the Government's drive to raise attainment along with and increasing focus on academic standards and testing puts too much pressure on children.
But the report dismisses the popular perception of a younger generation obsessed with fashion and relationships.
Only 4 per cent of children in the survey said they worry about clothes and fashion, while fewer than half (39 per cent) are worried about not being "cool" enough or not having a boyfriend or girlfriend (42 per cent).
Falling out with friends (77 per cent), health of family (70 per cent) and being attacked in the street (69 per cent), are also among children's most common fears.
More than half of the children reported that are worried about problems related to drugs and almost two-thirds worry about their appearance.
Two-thirds of teenagers are most likely to talk to their friends about their worries, but more than one-third said they would be too embarrassed.
Most also feel that they unable to confide in their parents for fear they would overreact, worry or tell them off.
Mary Marsh, NSPCC chief executive and a former headteacher, described the findings as a "major problem".
"Young people need to talk about their worries before they become all-consuming," she said.
Someone to turn to? is available at www.nspcc.org.uk