It follows a warning from teaching unions of an “explosion” in the number of such classes.
But the claims were dismissed as a “moanfest” by education secretary John Swinney as he came under fire at Holyrood yesterday.
A Freedom of Information request by the Scottish Conservatives showed 112 schools had combined classes for three levels, with a further 11 schools squeezing four topics into one class. This is from a total of 238 schools who responded.
These include Inverclyde Academy, where one class is being taught four different levels of maths at the same time, and Bridge of Don Academy in Aberdeen, which has 40 combined classes.
Perth High is teaching three levels in combined classes relating to chemistry, physics and biology.
And Ayr Academy is being forced to teach four different levels of English in one – National 3, National 4, National 5 and Higher.
Tory leader Ruth Davidson said: “Across Scotland, thousands of pupils are being thrown together in combined classes because the school doesn’t have the resources to teach qualifications separately. It’s unfair on the children who have to compete for the teacher’s attention and unfair on teachers who have to conduct up to four different lessons all at the same time.
“Experts across the board have told the SNP government about the damage and strain this causes and our data shows the scale of the issue across every part of the country.”
The EIS teaching union has warned of an “explosion” of such classes.
And the leaders of a second teachers’ union, the NASUWT, have complained the combined classes cause “intolerable workload or stress” for teachers.
Mr Swinney insisted multi-level teaching had been a feature of schooling Scotland for decades.
He told Ms Davidson what mattered was pupils’ achievements, which statistics showed were on the rise.
“What I am interested in is making sure our education system delivers the best outcomes possible for the young people of Scotland,” he said.
“And on that the evidence is substantial that the education system is doing exactly that,” the deputy First Minister told MSPs.
“We see young people now achieving more within our schools. We see attainment rising within our society, equipping our young people with the qualifications they require and we also see young people leaving school to the highest level of positive destinations in our history.”