Aron made his international debut for Iceland on 2 February 2008.
Aron was called up to the 2011 European Under-21 Championship Iceland squad, which took place in Denmark.
In the first match, Iceland beat hosts Denmark 3–1.
This was followed with a 2–0 loss to Belarus, where Aron was sent off.
The two losses saw Iceland go out of the tournament via a tie breaker.
Aron has been a regular player in the senior side since debuting despite helping the U-21 side when they qualified for the UEFA Under-21 Championship.

Aron was named as the permanent captain of the national team before a friendly match against the Faroe Islands in August 2012 at the young age of 23, ahead of his 29th cap.
Under his captaincy, Iceland qualified for the play-off round of FIFA World Cup qualification for the first time, where they lost 2–0 on aggregate to Croatia.

On 10 October 2014, Aron scored his first senior international goal in Iceland's 3–0 away win against Latvia in UEFA Euro 2016 qualifying.
He scored again in a 2–1 defeat of the Czech Republic on 12 June 2015.
On 6 September, he was sent off in the last minute of a goalless draw at Laugardalsvöllur in Reykjavík against Kazakhstan, a result which put Iceland into their first major international tournament.

Aron captained Iceland at their first major international tournament, UEFA Euro 2016 in France.
After their first match, a shock 1–1 draw with Portugal in Saint-Étienne, opposing skipper Cristiano Ronaldo refused to trade shirts with him.
Iceland finished second in their group, after beating Austria and drawing against Hungary, and then knocked out England in the round of 16.
They were defeated by France, 5–2, in the quarter-final.
Aron played in all five games.

In May 2018 he was named in Iceland’s 23 man squad for the 2018 World Cup in Russia.
Aron made his international debut for Iceland on 2 February 2008. Aron was called up to the 2011 European Under-21 Championship Iceland squad, which took place in Denmark. In the first match, Iceland beat hosts Denmark 3–1. This was followed with a 2–0 loss to Belarus, where Aron was sent off. The two losses saw Iceland go out of the tournament via a tie breaker. Aron has been a regular player in the senior side since debuting despite helping the U-21 side when they qualified for the UEFA Under-21 Championship.
Aron was named as the permanent captain of the national team before a friendly match against the Faroe Islands in August 2012 at the young age of 23, ahead of his 29th cap. Under his captaincy, Iceland qualified for the play-off round of FIFA World Cup qualification for the first time, where they lost 2–0 on aggregate to Croatia.
On 10 October 2014, Aron scored his first senior international goal in Iceland's 3–0 away win against Latvia in UEFA Euro 2016 qualifying. He scored again in a 2–1 defeat of the Czech Republic on 12 June 2015. On 6 September, he was sent off in the last minute of a goalless draw at Laugardalsvöllur in Reykjavík against Kazakhstan, a result which put Iceland into their first major international tournament.
Aron captained Iceland at their first major international tournament, UEFA Euro 2016 in France. After their first match, a shock 1–1 draw with Portugal in Saint-Étienne, opposing skipper Cristiano Ronaldo refused to trade shirts with him. Iceland finished second in their group, after beating Austria and drawing against Hungary, and then knocked out England in the round of 16. They were defeated by France, 5–2, in the quarter-final. Aron played in all five games.
In May 2018 he was named in Iceland’s 23 man squad for the 2018 World Cup in Russia.
Aron Gunnarsson