More than 70,000 pupils have missed more than half of school since 2019, figures obtained by the Scottish Conservatives show.
Meanwhile, more than 6,000 have not attended school at all in the past six years, according to freedom of information requests to councils.
The Tories said the data was “deeply alarming” and indicated the SNP’s “desperate failure in education”.
The figures showed that 73,184 pupils had an attendance rate of below 50%, while a further 6,270 pupils had no attendance between 2019/20 and 2024/25.
The total is likely to be higher as some of the attendance data was incomplete.
However, the Scottish Government says attendance rates are improving and persistent absences are declining.
Conservative MSP Miles Briggs said: “School attendance in Scotland is in crisis, and these figures show the truly shocking scale of the problem.
“It’s utterly unacceptable that so many pupils have missed at least half of their schooling – and truly terrifying that more than 6,000 have not attended school at all.
“This is yet another indicator of the SNP’s desperate failure in education.
“We know that the best place for most children to learn is in the classroom, so the fact that thousands are missing school is deeply alarming and risks long-term harm to their education and wellbeing.”
A Scottish Government spokesperson said: “It is hugely encouraging that the latest official statistics show the improvement in attendance and a fall in absences, including a noticeable reduction in persistent absence levels, which reflects the efforts of schools in responding to challenges since the pandemic.
“Any form of term-time absence disrupts learning and can impact attainment.
“It is therefore vitally important that parents and carers ensure that children attend school and should only arrange family holidays during the holiday period.
“National guidance is clear that education authorities and schools should engage with children, young people and families to support improved attendance and reduce absence, through understanding underlying concerns.”
The government said work to refresh national attendance guidance is ongoing with Education Scotland and councils.
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