In total, 2,284 teachers across 24 councils were impacted by stress in 2019/20 – a rise of around 26 per cent since 2016/17 when 1,808 were signed off, The Herald reported.
Edinburgh City Council, the Highlands and the Western Isles saw the largest rises.
Union leaders said the Covid-19 pandemic had “exacerbated” the mental health strain on teachers due to increased workloads, school closures and remote learning.
However, the Scottish Government pointed to a £1.5 million mental health support funding package that had been introduced due to the pandemic.
Larry Flanagan, EIS general secretary, said teachers were suffering due to “excessive workload”.
He said: “The last year of coping with the impact of the pandemic is likely to have exacerbated the pressures. It is critical, therefore, that as we look to education recovery, support must be put in place around nurturing teacher well-being as a prerequisite for doing the same for pupils.”
The rise led to criticism from the Scottish Conservatives which labelled the figures “hugely concerning”.
Education spokesman for the party, Jamie Greene, said: “Our hard-working teachers are bearing the brunt of the SNP slashing thousands of teachers from our classrooms.
“It is hugely concerning to see thousands of teachers getting signed off every year. With the lack of support from SNP ministers, they are feeling overworked and under appreciated.
"The more teachers that have to be signed off only adds to the pressure for our schools.
"The Scottish Conservatives will recruit 3,000 additional teachers for our classrooms and ensure they are the ones making the decisions that are best for their school’s needs."
Responding, an SNP spokesperson said the party had recruited an additional 1,400 teachers during the pandemic and it would recruit further after the election on Thursday.
The spokesperson said: “We recognise the stress teachers have been under to deliver learning throughout the pandemic and we have taken steps to reduce the workload of teachers by simplifying the curriculum and removing unnecessary paperwork.
“The government has also undertaken a recruitment drive by hiring 1,400 over the pandemic. Our manifesto has committed £1 billion to closing the attainment gap and recruiting another 3,500 teachers.”