Árni Þór Sigurðsson (born 30 July 1960) is an Icelandic diplomat and former member of the Althing.

At the Althing, Árni Þór represented Reykjavík Constituency North as a member of the Left-Green Movement until 2014.

Shortly after the closure of Iceland's embassy in Moscow in 2023,[1] Árni Þór became Ambassador to Denmark.

During the Klaustur Affair, it was revealed that Gunnar Bragi Sveinsson had appointed Árni Þór as an ambassador in order to draw attention away from Geir Haarde, whose simultaneous appointment was a political favour to the Independence Party.

[2] Árni Þór responded with a public statement emphasizing that his experience made him a good candidate for the role.