Barnardos says it now costs 785 euro to put a child through their first year of secondary school - an increase of 50 euro.
The children's charity says the overall costs of sending a child to school have gone up this year compared with 2014.
It now costs 365 euro for a senior infant - up 20 euro - while it's up ten euro to 390 for a child in 4th class.
The average price of books has increased by around 25 euro and voluntary contributions now average 150 euro.
Barnardos CEO Fergus Finlay says those contributions are a massive burden on parents.
Donegal TD Charlie Mc Conalogue says cuts in Government funding and the refusal to commit to a Minor Works Scheme for schools is contributing to the rising costs.
The Fianna Fail Education Spokesperson says capitation grants have been cut, and schools are left relying on voluntary contributions.......