Thousands of pupils are to be fast-tracked through their first national exams a year early.
The exams are usually taken in fourth year
Pupils in East Renfrewshire are to take Intermediate exams, the new equivalent of Standard Grades, at the age of 14.
The council said it hoped it would enable pupils to make better use of their early years in secondary school.
The Scottish Secondary School Teachers' Association said it was concerned the system may be inflexible and children would be hothoused.
An increasing number of councils have been letting some pupils start work a year early for Standard Grades or the new equivalent, Intermediate exams.
Last summer Keith Grammar in Moray went a stage further putting the entire third year forward for the exams early.
However, the results for the S3 pupils were below the level for fourth year pupils.
At the time SSTA general secretary David Eaglesham said the project was social engineering rather than education.
East Renfrewshire Council is taking the revolutionary step of making fast-tracking the norm in all its schools.
It said this would make better use of the second year in secondary when often there was not much asked of children.
It will give pupils an extra year to study for the difficult exams of Highers and weaker pupils could choose to go at a slower pace, the council said.
The council's head of education Ian Fraser said the fast-track move was being considered for two reasons.
"One is the increased attainment and better skills and abilities of pupils coming from primary schools into secondary and they are performing at a higher level than previously," he said.
Keith Grammar tried the experiment last year
"Secondly, it's trying to look at the top end of the system - the gold standard, the higher grade awards - and trying to give youngsters more time to prepare for Highers.
"One of the ways to do that is to adjust what's happening in the first few years of secondary education."
He added: "East Renfrewshire is a high attaining authority and is very inclusive with a great regard for young people with difficulties in learning as well."
Mr Eaglesham said: "The danger is that we put all the young people in a year group together and say that they must all move at the same pace, at the same time, regardless of what their background has been or how able they are to learn.
"Young people develop at different rates and we need to reflect that in what happens with examinations."