Ólafur Arnalds (Icelandic pronunciation: [ˈouːlavʏr ˈartnalts]; born 3 November 1986) is an Icelandic multi-instrumentalist and producer from Mosfellsbær, Iceland. He mixes strings and piano with loops and beats, a sound ranging from ambient/electronic to atmospheric pop. He is also the former drummer for hardcore punk and metal bands Fighting Shit, Celestine, and others.

In 2009, Ólafur also formed an experimental techno project, entitled Kiasmos, with Janus Rasmussen from the Icelandic electro-pop band Bloodgroup, announcing his electronic debut album in 2014.

In 2013, Ólafur composed the score for the 2013 ITV series Broadchurch, for which he won the 2014 BAFTA TV Craft Award for Best Original Music.

In 2020, Ólafur was nominated for a Primetime Emmy Award for Outstanding Original Main Title Theme Music, for his title theme to Apple TV+ series Defending Jacob.

In 2021, he was nominated in two categories at the 64th Annual Grammy Awards. "Loom (feat. Bonobo)" was nominated in the Best Dance/Electronic Recording category and "The Bottom Line" was nominated in the Best Arrangement, Instrumental and Vocals category. Both songs appear on his fifth studio album Some Kind of Peace (2020).