The percentage of Northern Ireland students receiving A* and A grades at AS and A-level was the highest among the UK regions, despite having fallen from last year.
Provisional figures published by the Joint Council for Qualifications showed 37.5% of pupils received the top grades at A-level, down from 44% in 2022.
At AS-level, 33.5% of entries got an A, compared to 38.8% last year.
The JQC said the results are still higher than pre-pandemic years and "reflect the continuing journey to pre-pandemic grading".
Thousands of pupils across Northern Ireland are receiving their results on Thursday.
The percentage receiving A* and A grades at A-level (37.5%) was higher than the UK average of 27.2%, while Wales had 34% and England had 26.5%.
This was the second-time students have undertaken summer exams marked and graded by exam boards since 2019.
