David Mar Stefansson is an Icelandic screenwriter, currently based in Reykjavík and London. He began his career as a journalist before transitioning to screenwriting, earning a BA in philosophy and creative writing with first-class honors from the University of Iceland and an MFA in screenwriting with honors from Columbia University in New York.

Stefansson has written several award-winning short films that have been showcased at festivals across the globe. He made his television debut with the miniseries Katla for Baltasar Kormákur and Netflix in 2021, writing four of the eight episodes. He also wrote for the third season of Trapped, which premiered on Netflix in 2022. His recent projects include writing the upcoming third season of Gangs of London for AMC and Sky, as well as the historical miniseries King and Conqueror for CBS and BBC. Stefansson’s horror feature Auteur is currently in development with Wild Atlantic and 6th & Idaho producing, while an original TV series of his is in development with David Heyman’s Heyday.