The percentage of P1-P3 pupils in classes of size 18 or less in Perth and Kinross has dropped from 26.6% in 2011 to just 15% in 2014, the lowest number since 2009.
Mid-Scotland and Fife MSP Murdo Fraser has accused the SNP of failing pupils in Perth and Kinross despite promising, in 2007, to reduce class sizes.
The Summary Statistics for Schools in Scotland also raised concerns that as many as one in five school buildings were in an unsatisfactory condition.
It highlighted the fact the number of pupils attending schools in Scotland increased from 673,530 last year to 676,955 in 2014.
Mid-Scotland and Fife MSP Murdo Fraser said:
“The SNP promised they would cut primary school class sizes to ensure every child in Scotland gets the best possible start in life. This isn’t happening.
“In Perth and Kinross the percentage of primary school children in classes of less than 18 children has reduced from a high of nearly 27% in 2011 to 15% this year.
“Before the SNP came to power the figure stood at just under 20% so there is no excuse for their failing record.
“Class size numbers are a huge concern for parents in Perth and Kinross, and one that must be treated as an absolute priority.
“It’s clearly wrong that children in one part of the country are taught in congested classrooms, while those in different council areas have a far more beneficial environment.”