Primary School children as young as four-years-old were among those who received suspensions in Northern Ireland, according to a report by the Education and Training Inspectorate (ETI).
The stats for the 2016/17 academic year show that 4,084 pupils of compulsory school age were suspended, with boys accounting for roughly three quarters of total suspensions.
The ETI notes that "alarmingly" 286 of the suspensions were of primary school age, 74 of which were in primary one or primary two.
Chief factors leading to suspensions includes repeated infringement of school rules.
'Uncertainty, delay and frustration'
The ETI's biennial report - Learning Lessons: Inspiring People: Putting Learners First - was published on Wednesday and sets out challenging times in education, noting a recent Audit Office report finding that the general schools' budget has fallen in real terms by 9.3% from 2012-13 to 2016-17.
Powersharing government in Northern Ireland has been in suspension since January 2017 which has left senior civil servants in charge of departments instead of ministers.
The ETI report said the absence of an education minister was restricting the decisions that can be made, which in turn creates "further uncertainty, delay and frustration".
The report also revealed further challenges to the sector in a rise in the number of "under-age children" - those aged two - in nursery units.
It found that at 25 of the 338 statutory nursery schools and nursery units within primary schools, a quarter of the children were two.
"Where there is a larger number of under-age children in a class, including those with additional needs, the demands on the practitioner to provide a quality pre-school programme is restricted and, as a result, the children do not make as sure a start as expected," the report found.
'Positives should be celebrated'
ETI chief inspector Noelle Buick emphasised that education and training in Northern Ireland has "many positives that should be celebrated".
She described many "exceptional" and "inspirational" leaders, teachers, lecturers and youth workers.
Ms Buick commended high standards in maths and good development of thinking skills at primary schools.
However she also highlighted concerns including large gaps in attainment in public exams and a growing number of primary one children being overweight.
The report includes a large and wide-ranging number of findings.
These include a large attainment gap for school leavers achieving at least five GCSEs at grades A*-C, including English and maths, between those who received free school meals and those who did not.
In 2016/17 47.5% of those receiving free meals reached this standard, compared with 77.4% of those who did not receive free meals.
"Exam results continue to show improvement, however large gaps in attainment are still not being addressed with the necessary urgency and energy," Ms Buick said.
"Pupils on free school meals continue to underperform overall and there is a gap in performance between boys and girls."
The report also revealed that a fifth of Northern Ireland's children entering primary school are overweight. This rises to one in four by year eight.
Mental health issues were also flagged in the report which found that a "significant number" of school children are impacted.
The report quoted local research that found 45,000 children in Northern Ireland have a mental health problem and one in five pupils "are suffering significant mental health problems by the time they reach 18".