New figures show over 1,300 citizens of Poland acquired Irish citizenship in 2016, making them the single largest group to do so.
The numbers from Eurostat also show that citizens of India and Nigeria were the second and third highest respectively.
While the number of UK nationals acquiring citizenship of another EU member state more than doubled in 2016.
Overall, member states granted citizenship to almost one million persons in 2016.
This was up from 841,000 in 2015 and 889,000 in 2014.
Moroccans, Albanians and Indians were the main recipients across the bloc.
Of the total number of persons obtaining citizenship of one of the EU states, 12% were former citizens of another EU member state, while the majority were non-EU citizens or stateless.
The largest group acquiring citizenship of an EU state where they lived in 2016 was citizens of Morocco (101,300, of whom 89% acquired citizenship of Spain, Italy or France), ahead of citizens of Albania (67,500, 97% acquired citizenship of Italy or Greece), India (41,700, almost 60% acquired British citizenship), Pakistan (32,900, more than half acquired British citizenship), Turkey (32,800, almost half acquired German citizenship) and Romania (29,700, 44% acquired Italian citizenship).
The number of citizenships granted actually fell in three states in 2016, with the largest decrease in Ireland (from 13,565 to 10,038 or -26%).
While Eurostat says the number of UK nationals acquiring citizenship of another member state more than doubled in 2016.
The number more than doubled from 2,478 people in 2015 to 6,555 people in 2016.