More children are in "supersized" classes in Clare than in most other counties in Ireland.
85 per cent of primary puils in the county are in classes greer than the EU average of 20, which is higher than the national average.
Over 3,400 of Clare's primary school students are in classes of at least 30 pupils, while more than 11,800 here are in classes of 20 or more.
The figures from the INTO show over a quarter of young students here are in so-called super-sized classes, though this number has fallen slightly.
The Irish National Teacher's Organisation says the potential of school pupils is being compromised by these larger classes and is calling for a progressive plan over the coming years to bring numbers down.
The union says the matter should be an educational priority in the upcoming budget, and estimates the cost of doing this at 15 million euro.
Assistant General Secretary Peter Mullan says the number of children in supersized classes in Clare is higher than the national average.
Principal of Ennis National School Ray Mc Inerny says he's not surprised by the latest figures
