A-level and GCSE students will be awarded the grades predicted for them by their teachers, the Welsh Government has announced.
The U-turn followed criticism from students, opposition politicians and Welsh Labour backbenchers.
Education Minister Kirsty Williams said she took the decision to maintain confidence in the system.
A total of 42% of A-level grades predicted by teachers had been lowered when results were published last week.
An UK government announcement is expected for England later.
The decision also affects AS-levels, skills challenge certificates and the Welsh Baccalaureate.
Those who received higher grades than those predicted by teachers will keep them.