The Police Scotland figures show that 80 school pupils were found with knives on school premises between the start of April and the end of November last year.
There were a further 19 cases of knives being used in “other criminal activity” at schools and 45 cases where pupils were found carrying an offensive weapon.
Despite the tragic killing of teenager Bailey Gwynne at Cults Academy in Aberdeen, children attending schools in the north-east of Scotland are among the most likely to be caught with knives.
The 16-year-old died in October, 2015, after being attacked by another pupil. A report found his death could have been avoided if his classmates had told teachers his killer was carrying a knife.
The statistics show that 11 pupils attending schools in the north-east were caught with knives over the eight-month period – the joint highest figure alongside the Lothians and Scottish Borders.
The data, described last night as “hugely concerning”, relates to the period after the Scottish Crime Recording Board changed the way knife crime in schools was recorded in April last year.
It forms part of a wider examination of knife crime in school carried out by Johnston Press Investigations Team.
It shows that children as young as four are being caught in school armed with knives and other lethal weapons, including prison-style “shanks” made by fixing razor blades into felt-tipped pens.
Other weapons schoolchildren were caught carrying last year included machetes, hunting knives and axes.
The investigation reveals a 42 per cent increase in children caught in possession of a knife, blade or other weapon over the last two academic years in areas where comparative figures are available.
Some areas of the UK have seen bigger increases, including rural counties – the problem is not confined to cities. Overall, reported knife crimes in schools have increased by 12 per cent.
In South Yorkshire there has been a 151 per cent rise in the number of children caught carrying knives in school over the last two academic years.
Just last week a 14-year-old boy was left permanently disfigured in an alleged attack with a bladed weapon outside a Glasgow secondary school.
Liz Smith, MSP, education spokeswoman for the Scottish Conservatives, said: “These statistics are hugely concerning, and show that we have a real problem.”
A Scottish Government spokesman said: “It is important that these figures are seen in the overall context of a 64 per cent reduction in crimes of handling offensive weapons in the last decade. We are determined to continue making progress – and the decision to specifically record offences of possession of weapons in schools was precisely in order to support efforts to make Scotland’s schools safer.”