Irish students are ninth out of 49 countries when it comes to maths, according to new figures.
That figure is an improvement from 17th out of 50 countries in 2011.
The TIMSS (Trends in Mathematics and Science Study) study shows Irish students are among the best in the world in terms of maths.
The results were poorer for science - with Irish fourth class students ranking 19th (slightly up from 22nd in 2011) and second year secondary students placing 10th overall.
In maths, Irish students are ahead of countries including England, the United States, Canada and Australia, according to the figures.
Meanwhile, Northern Irish primary school students are well ahead of their counterparts in the Republic when it comes to maths, according to the study.
The TIMSS figures show Northern Ireland is sixth in the world, comkpared to ninth in the Republic.
Just 14% of students in the Republic achieved the highest 'advanced' grade. That compares to 27%b who reached the top mark in maths north of the border.
The TIMSS study assesses the mathematics and science achievement of pupils in the Fourth and/or Eighth grades (equivalent to Fourth Class and Second Year in Ireland). First conducted in 1995, TIMSS takes place every four years.
The most recent TIMSS assessment took place in 2015. It is the results of that study that are being published today.
Education Minister Richard Bruton said: "While there has been some progress, it is clear that we have a long way to go if we are to achieve our ambition of being the best in Europe."