Pupils in East Kilbride and Strathaven will not sit Higher and Advanced Higher exams next year.
Education Secretary John Swinney confirmed pupils’ final grades will be based on the judgement of their teachers.
He said the decision was based on the disruption that COVID has caused to the education system rather than safety concerns.
The country’s National 5 exams have already been cancelled.
The Scottish Government had previously said a final decision on whether the exams would go ahead would not be taken until the middle of February.
A leading teaching union and opposition politicians have now called for clarity on the detail of any assessment to avoid the exams’ fiasco of this summer.
Thousands of students from deprived backgrounds were initially downgraded before a u-turn by the Scottish Government.
Labour MSP Monica Lennon said the decision to cancel one-off exams “made sense” as too many pupils have missed out on vital schooling through self-isolation.
But she accused the Education Secretary of “dithering for months” and letting down pupils and teachers.
Ms Lennon added: “It’s unfair that we are halfway through the school year before this decision has been taken.
“Pupils and teachers now need clarity on what the details of the alternative assessment model will be.
“We need urgent assurance that it will have will have teacher judgement at its heart, take full consideration of disruption to learning and avoid the repeat of the unfair outcomes that happened earlier this year.”
The Educational Institute of Scotland (EIS), the country’s largest teaching union, has welcomed the fact that a decision has been made.
But say agreement must be reached on appropriate recognition of the additional workload required in any alternative assessment programme.
EIS general secretary Larry Flanagan said: “The EIS has every confidence in the ability of teachers to make professional judgements based on pupil evidence and in the circumstances believes that cancelling the exam diet in favour of an alternative model is the correct decision, one which could have been made earlier.
“We have raised repeatedly, however, the additional workload burden which this will generate and made clear that teachers should not be treated as unpaid SQA markers.
Mr Flanagan added: “The announcement acknowledges the significant level of disruption that students have faced during the pandemic.
“It is essential that all possible steps are taken to ensure that no young person is unfairly disadvantaged as a result of becoming ill or being required to self -isolate due to COVID-19.
“Given the significant impact of the pandemic on many young people, particularly those from less advantaged backgrounds, it is a common-sense decision that is in the best interests of students.”
The SNP’s Linda Fabiani said: “Given the disruption to pupils prior to the summer holidays and the fact some will have had to self-isolate, perhaps on numerous occasions, these proposals are not only safe, but in my view are fair.
“Our Education Secretary has listened to Teachers Unions and acted accordingly. I look forward to seeing further details to ensure the process of grading pupils is done in done in a just and credible manner.
“Hard decisions have had to be taken in the best interests of our young people, and I have confidence that our teachers will do their best for all of their pupils.”
