School pupils in Perth and Kinross are three times as likely as those in Angus to be officially listed as having additional support needs.
The disparity has been revealed by a campaign group who are worried that thousands of young Scots may be missing out on the extra help to which they are entitled.
It has called on councils to do more to identify and record pupils with attention deficit disorder, autistic spectrum disorders and dyslexia or who have sight or hearing problems, are in care or are suffering emotional difficulties resulting from bullying or bereavement.
Figures show large variations in the proportion of pupils in different local authorities who are known to have additional support needs (ASN), including substantial differences in Courier Country.
In Angus, 9% of primary pupils and 10% of those in secondary were listed with ASN last year. However, in neighbouring Perth and Kinross the figure was 29% for both categories giving it one of the highest rates in the country.
The Scottish average was 18% in primary and 19% in secondary. Aberdeenshire, Clackmannanshire and Stirling were all above average, while Dundee and Fife were both below.
As an example of the effect of the differing rates, Dundee had 741 secondary pupils listed with ASN last year one fewer than Clackmannanshire even though its total population is roughly one third that of the city’s.
Local authorities are required by law to provide extra support to ASN pupils, whose numbers have increased by 89% to 131,000 in the past decade, but the Scottish Children’s Services Coalition believes that some are not living up to their obligations.
Spokeswoman Sophie Pilgrim said: “We find it increasingly frustrating that we simply cannot get precise figures on the number of children with ASN and this raises concerns as to whether some local authorities are fulfilling their statutory requirements.
“The Scottish Government must commit to working more closely with local authorities to tackle this and develop a universal method to ensure that better information is recorded so that accurate numbers can be reported.”