Smartphones are making children as young as nine turn up for school tired because they are waking to check devices more than 10 times a night, experts have warned.
Pupils said they were reluctant to turn off their mobile devices at night because of 'fear of missing out'.
The new major study - and the first of its kind commissioned by a group of leading headteachers - revealed that a quarter of children feel tired during the day because they have been up at night responding to phone notifications.
However, one in 10 said they would feel stressed about missing out if they didn't check their mobile devices before going to bed.
This trend of the fear of missing out - known in social media circles as "FOMO" - has meant primary and secondary school pupils are sleep deprived.
One in 10 youngsters aged 11 to 18 spend more than an hour on their mobile device after going to bed, the research by Digital Awareness UK (DAUK) revealed.
Experts warned that many parents are often ignorant of the frequency at which their children are checking mobile apps like Twitter, WhatsApp and Snapchat at night.
In some cases they said teenagers received more than 100 notifications throughout the night with many of them being unaware of how to turn them off.
But nearly four in 10 admitted to wanting to know what was happening if they didn't check their devices.
The survey of 2,750 pupils was commissioned by the Headmasters' and Headmistresses' Conference (HMC), which represents top private schools, following fears of the effects technology was having on children.
It polled both private and state schools with an even split between boys and girls.
Some 68 per cent said going on their mobiles at night affected their school work, while 32 per cent of children with the most excessive use said their parents were unaware of their nocturnal habits.
Nearly seven in 10 of the pupils polled said that using their mobile devices at night affects their school work.
Charlotte Robertson, DAUK co-founder, said: "The youngest (child checking their devices at least 10 times a night) is about nine, and many parents are very unaware of it.
"One of the biggest topics around at the moment is excessive social media consumption and how it is affecting our physical and emotional well-being.
"A lot of them are waking up sometimes with over 100 notifications from conversations that have happened overnight.
"They want to be that person that is responding at 1am, and seen to be quite cool, to make sure they catch the joke - it's a huge driver, that anxiety of wanting to know what's happened."
Mike Buchanan, chair of HMC, added: "As teachers we are seeing the effects of device use every day. If they are not socialising with each other, or are tired for lessons and not concentrating, we need to address that.
"We want to start a new conversation with parents about how to influence teenagers' responsible use of phones and other devices both at home and at school."
This is the first survey of its kind investigating use of mobile devices overnight and the impact on children's health and wellbeing. Last year a study by Glasgow University revealed teenagers who engage with social media at night were at risk of damaging their sleep and increasing their likelihood of depression and anxiety.