The measures introduced in Budget 2024 are "demoralising and disappointing", according to the Irish National Teachers’ Organisation (INTO).
Some 740 teachers will be introduced to support those with special educational needs as part of Budget 2024.
Minister Paschal Donohoe also announced that the free schoolbooks scheme to be extended to Junior Cycle secondary school students.
A fee waiver will also be introduced for school transport and State exams.
Child Benefit will be expanded to include 18-year-olds in full-time education.
INTO said the Government missed an opportunity to address class sizes, and General Secretary John Boyle said today’s primary education budget "lacks any ambition".
"The demoralising, deleterious, disappointing and discouraging education budget for 2024 signals that our national shame of super-sized classes is set to continue beyond the lifetime of the current government," he said.
“There’s no getting away from the fact that Ireland’s primary school classes are the highest in the Eurozone, remaining almost 3 pupils per classroom more than the average throughout the EU."
He said 83% of classes are larger than the EU average of 20, with 60,000 pupils in classes of 30 or more.
"Today’s no-change announcement will add to overcrowding in schools," Mr Boyle said.
"Our politicians had a once in a lifetime chance to reach the EU class size average. They missed an open goal.”
Labour Education Spokesperson Aodhán Ó Ríordáin also criticised the Government for not addressing class sizes in Budget 2024.
"Large class sizes have a negative impact on learning outcomes. They make it difficult for teachers to give individual attention to each student," he said.
Hot School Meals
Social Protection Minister Heather Humphreys welcomed the announcement that the Hot School Meals Programme is set to be expanded to a further 900 schools next August.
This expansion means children will have access to hot food in over 2,000 primary schools around the country.
Ms Humphreys in 2024, the Government will be two-thirds of the way to providing hot meals to every primary school in Ireland.
“It is a major step on the path to delivering my ambition that every child born today will receive a hot school meal by the time they reach school-going age,” she said.