Three in 10 A-level entries scored at least an A grade this year as Northern Ireland students performed strongly.
Figures showed 30.4% received grades A* or A, an increase of 0.9% percentage points on the previous year.
The gap between girls and boys widened as, for the first time, the latter's results slumped when compared across all grades.
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Despite a year of major change to the qualification, performance remained stable, said awarding organisation the Joint Council for Qualifications (JCQ).
Chief executive Justin Edwards said: "There are reforms and changes going on within the A-level system so to have stable outcomes ... is important and I am pleased that Northern Ireland candidates continue to do strongly."
He said there was plenty of "head room" for further inflation in grades in the years ahead without hampering universities' ability to choose between pupils.
The "decoupling" of AS-levels from A-levels in England, entailing a move away from coursework and modular exams throughout the course, has seen a drop in the number taking AS-levels in Northern Ireland.
A proportion of the qualifications there come from English awarding bodies.
The gap between girls and boys widened across all grades.
Mr Edwards said this was due to an increase in outcomes for girls and a decrease for boys.
Girls now outperform boys by 1.5 percentage points at the A* grade and 6.5 percentage points at A*-A.
The chief executive added: "For a first year we have boys' outcomes decreasing and girls' outcomes increasing well and strongly so we need to keep an eye on that."
There were 30,684 A-level entries this year.
The proportion of those awarded an A* increased by 0.4 percentage points to 8.1% of entries.
Other key findings included:
- The overall A*-E pass rate remained stable following a 0.1 percentage point increase to 98.3%.
- The proportion of girls earning an A* increased by 0.9 percentage points to 8.7% and at A*-A by 2 percentage points to 33.3%.
- Boys' performance declined by 0.3 percentage points to 7.2% awarded an A* and at A*-A by 0.4 percentage points to 26.8%.
- The proportion of A-level entries saw a slight decrease of 3.6%, in line with the overall school population decrease.
- Subject choices remained broadly stable, with mathematics continuing to be the most popular.
- The proportion of science, technology, engineering and mathematics (Stem) entries decreased to 39.2% of all A-level entries, down from 39.8% last year.
There was a pronounced increase in the number of girls taking computing, up by two thirds.
More girls have taken Stem subjects over the last four year but there has not been the same rate of growth this year.
French and German studies decreased.
The number of A-level Irish entries have been increasing since 2013, they were up 0.1% this year.
Anna Murray achieved four A*s in biology, chemistry, history and French.
The pupil at Our Lady and St Patrick's College Knock in East Belfast is going to Queen's University Belfast to study medicine.
She said: "I just feel so grateful and so blessed."
Tiarnan Curran-Feeney, from the same school, was awarded A*s in maths, further maths and physics and an A in biology.
He is taking a gap year and applying to study maths at Oxford the following year.
"I just get great enjoyment from working with numbers and trying to solve problems," he said.
"My favourite thing is a question I am looking at for ages and suddenly realising after you were staring at it that there was a really simple way to do it.
"I am just so happy at the moment, over the moon."
Emer Maguire, from St Patrick's, was awarded three A*s in sociology, religion and business studies.
She is weighing up psychology at University College Dublin or business management in Glasgow and is interested in pursuing criminal psychology.
Emer logged on to receive her results but could only get two because of the different awarding bodies and had to go to school for the third.
It took her 20 minutes to open the pin but it was worth it when she finally got in.
"I honestly thought it was not me and kept checking my name to see that it was someone else's but it was definitely me," she said.
"I am just over the moon."
