The Organisation for Economic Co-operation and Development (OECD) found school staff in Scotland spend an average of 855 hours a year teaching, compared to an international average of 704 hours.
Only teachers in Mexico, the United States, Chile and Argentina spend longer in the classroom.
Workload in Scotland has dropped by 10% in the decade between 2000 and 2010, but the figure does not include time spent preparing lessons, attending meetings and marking pupils’ work.
In addition, the report by the OECD, which looks at 38 countries, also found classroom teachers in Scotland were the eighth best paid in the developed world.
Countries ahead of Scotland – where non-promoted teachers can earn up to £34,200 – are Denmark, Ireland, Canada, the Netherlands, Germany, Switzerland and Luxembourg.
Scottish teacher pay has increased in real terms by 21% over the past decade as a result of the decade old McCrone deal on pay and conditions, which addressed a long-standing decline in salaries.
The Educational Institute of Scotland (EIS) teaching union said the figures showed the dedication of Scotland’s teachers.
Larry Flanagan, general secretary of the EIS, said: “In an environment of budget cuts, falling teacher numbers and rising class sizes, local authorities and the Scottish Government must look very closely at this report and consider how they can better support Scotland’s teachers and Scotland’s education system.”
Overall, the OECD report concluded that governments should increase investment in early childhood programmes as well as maintain “reasonable costs” for higher education to reduce inequality, boost social mobility and improve people’s employment prospects.
Education at a Glance 2012 reveals stark differences between countries in the opportunities they offer young people to enter higher education, notably for children of poor families or whose parents have had a limited education.
Angel Gurría, OECD Secretary-General, said: “Countries need an increasingly educated and skilled workforce to succeed in today’s knowledge economy and investing from an early age is crucial to lay the foundations of later success.”
The report found Australia, Finland, Ireland and Sweden had the highest success rates in the OECD for young people with poorly-educated parents getting a degree.
But in Italy, Portugal, Turkey and the United States, more than 40% of young people from low educational backgrounds have not completed upper secondary education, and less than 20% have college or university qualifications.
“Enrolling children early in formal education and keeping schools mixed in terms of social backgrounds have more impact in boosting educational equality than other factors, such as parental support or the cost of tuition fees,” the report said.
“Addressing inequality early is key as little can be done to remedy poor outcomes later in school, without compromising the quality of higher education.”