A Freedom of Information request to NHS Trusts in England by the NSPCC found schools seeking professional help for pupils from NHS child and adolescent mental health services (CAMHS) made 123,713 referrals since 2014/15.
Overall the number of referrals has increased each year since 2014/15, reaching 34,757 in 2017/18 - the equivalent of 183 every school day.
Over the four-year period the majority of referrals (56 per cent) came from primary schools.
Of NHS trusts that were able to provide information, nearly a third (31 per cent) of referrals from schools to CAMHS were declined treatment as they did not meet the criteria for support.
Peter Wanless, chief executive of the NSPCC said: "Our research shows schools are increasingly referring children for specialist mental health treatment, often when the child is at crisis point.
"Childline plays a vital role in supporting children with their mental and emotional health, and many turn to us when they are struggling to get access to specialist treatment.
"We have seen a marked increase in counselling about mental health, and fully expect it to continue. It is vital that government urgently provides more funding to Childline and help children who don't have access to support elsewhere."
The government has pledged a raft of children's mental health services improvements as part of the December 2017 green paper Transforming Children and Young People's Mental Health, backed with £300m in extra funding.
However, the education select committee has criticised it for "lacking ambition", claiming it will provide no help to the majority of children who desperately need it.
Dr Max Davie, officer for health promotion for the Royal College of Paediatrics and Child Health said the statistics further highlight the pressures mental health services are under in England.
"What's particularly concerning is the fact that 56 per cent of referrals came from primary schools," he said.
"Paediatricians working in the community have also noted a surge in referrals for emotional and behavioural difficulties, often once CAMHS have rejected the referral.
"As professionals who work closely with local authorities we are aware of widespread cuts to behavioural support in the educational sector, leaving schools exposed and unsupported.
"At the universal level, we need personal, social and health education at all primary and secondary schools, so that children can self-manage better."
"But only a system-wide overhaul of agencies concerned with children's mental health will allow us to identify children developing mental health problems (including behavioural disorders) and allow for assessment of need and appropriate multi-agency support, thus preventing them from getting to crisis point.
"We need a 'local offer' laying out pathways and early interventions for children who are starting to run into trouble."
CYP Now is hosting a one-day conference on 29th June, Mental Health in Schools: Good Practice in Buillding Resilience