Two-thirds of pupils who care for ill or disabled family members say their schools do nothing to help them cope with this responsibility.
A survey of 350 school-aged carers, conducted by the Children's Society, reveals that only a third feel adequately supported by their schools and teachers.
The charity's Jenny Frank admits that this comes as little surprise. "A lot of young carers will go to great lengths to conceal what's happening at home," she said.
"They're worried that they will be teased or bullied. Many worry about being taken into care.
"Young people really want schools to understand them more, but they're afraid to ask for help. It's a Catch-22 situation."
There are approximately 175,000 school-aged children in Britain who have responsibility for an ill or incapacitated family member.
Their school attendance is often sporadic because caring responsibilities keep them at home. Others are consistently late because they accompany younger siblings to school every morning.
Many struggle to pay attention during lessons, or to finish their homework. Others become stressed or angry, and express this as classroom misbehaviour.
"What they find difficult is what they feel inside: stress, anxiety, worry," Ms Frank said. "That's why it's so helpful to have somebody in school they can talk to."
Jamie Harrett agrees. The 14-year-old spends each evening helping to feed, bath and entertain his 12-year-old autistic brother. For several years, he was bullied at school and he finds it difficult to keep up with his homework.
On one occasion, he was threatened with detention after problems with his brother forced him to hand homework in late.
"The teacher didn't seem to believe me," he said. "She thought it was no excuse because we'd had a few weeks to do the work.
"I really, really try to get my homework done on time, because they don't understand. I try to start it in the school library at lunchtime, to get it done as quickly as I can.
"That gives me a bit of a jumpstart when I get home. It makes it a bit easier."
But he would like to see the problems faced by young carers discussed publicly during school assemblies. "People would be more understanding then," he said.
Zoie Brown, who is responsible for pastoral care at Kings' School in Winchester, agrees that teacher empathy is vital for young carers.
She runs a series of assemblies and lunchtime clubs for carers and their classmates.
"If there's a problem with a child, if there's a pupil not behaving well or not very happy, there are systems in place to help them," she said.
"Teachers are aware of people in their tutor groups, in their classes. Heads of year look out for their cohort. There are a lot of people around who can pick up on things."
And, says Jamie, it is often helpful just to be understood. "Without my caring responsibilities, I wouldn't be the same as how I am, as mature as people say I am," he said.
"It's made me grow up a lot quicker. But I'd like people to accept it, accept how hard it is."