The rankings examine how many countries holders can visit without a visa
Tánaiste and Foreign Affairs Minister Simon Coveney has welcomed the announcement that the Irish passport is ranked fifth highest in the world.
The Henley Passport Index ranks Irish passports at fifth in the world - alongside Portugal, the US and South Korea.
While Arton's Global Passport Index says the Irish passport is fourth, in terms of a visa-free score.
This listing puts Irish passports on a par with countries like Canada, Switzerland and the US.
The rankings measure passports of the world according to the number of countries their holders can travel to visa-free.
Germany tops both lists.
Minister Coveney has welcomed the announcements, saying: "I am very proud to see the Irish passport ranked fourth and fifth respectively in two prestigious global rankings.
"The ranking demonstrates again the value and power of the Irish passport and how well it is regarded internationally."
The Tánaiste also congratulated staff of the Passport Service, saying this announcement also brings attention to "the highly secure nature of the Irish passport".
"It reflects the major efforts undertaken at all levels of the Passport Service to protect the integrity of the passport and to ensure it continues to be a secure travel document, while also meeting the challenges of increases in application numbers and the need for technological advancement", he adds.