Nearly 40,000 secondary school pupils are taught English and maths in classes of more than 30, according to official figures.
Ministers' target has not been met
The totals for S1 and S2 children are detailed in a National Statistics publication.
The Scottish Executive has promised to slash the class sizes to 20 in S1 and S2 for maths and English by 2007.
The pledge was made in the partnership agreement signed by Labour and
the Liberal Democrats, on forming the power sharing government after the May election.
The latest publication showed that in September this year 24,002 pupils were taught maths in class sizes over 30 - representing 20% of the total.
The report also said that 14,288 students were taught English in class sizes over 30, which amounted to 12% of the age group.
Education Minister Peter Peacock said: "The executive's partnership agreement sets out our commitment to reduce class sizes in S1 and S2 maths and English to 20 from the current maximum of 33.
"The data we have published will be used to help benchmark progress towards
achieving this target and our aim of providing more focused, individual attention for pupils to improve performance in these key subjects and help close
the attainment gap."
"The results will be also be used as part of the annual workforce planning exercise to estimate the number of additional teachers required to meet our S1 and S2 commitments."
Official figures for primary class sizes are due out in the spring.