Funding for Additional Support Need pupils falls by £1,000 per child
Children with additional support needs (ASN) are receiving £1,000 less per pupil compared to 2012, figures show.
While overall Scottish government funding is up by £200m, the number of pupils with ASN has increased 89% - from 118,011 to 215,897.
The Scottish Children's Services Coalition said more money was "vital" for vulnerable pupils.
But the Scottish government said local councils were responsible for "meeting the support needs of their pupils".
The Scottish government figures were published in response to a written question to Education Secretary Shirley-Anne Somerville.
They showed the average spend per pupil with ASN in Scottish primary schools, secondary schools and special education facilities dropped from £4,276 in 2012 to £3,224 in 2020 - a fall of 24.6%.
However spending in cash terms per pupil ranged from £1,737 in Edinburgh to £5,849 in the Shetland Islands.
While 30.9% of all children at Scottish schools had ASN, the number of full-time equivalent ASN teachers at publicly funded schools fell from 3,389 to a record low of 2,836.
Stephen McGee of the Scottish Children's Services Coalition told BBC Good Morning Scotland the number of children with ASN had increased "exponentially" and local councils were "making decisions" on where money was being allocated.
He also said teachers were "stretched" as they were being asked to perform roles in parenting, social work and mental health. The solution, he said, was to employ "specialists" for these roles.
Mr McGhee added: "A disproportionate cross section of the young people who have ASN will also come with a background of lower income families and come from areas of deprivation.
"When you put the three together you have young people who don't have access to higher and further education in the same way that their cohorts might.
"That puts them at more detriment in terms of further learning availability and access to jobs so it has an effect right through their lives if this isn't picked up, assessed and resourced at the correct moment."
Enhanced capacity
The Scottish government said all children and young people should receive the support they need and that teacher numbers were at their highest since 2008.
But it said councils were responsible for "identifying and meeting" the additional support needs of their pupils.
A spokesman added: "We provide councils with an additional £15m each year to further enhance capacity to help meet the individual needs of children and young people.
"This year, 1,354 extra pupil support assistants were recruited, exceeding a Programme for Government commitment to deliver 1,000 new support assistants."