Þorsteinn Bachmann (born 25 October 1965) is an Icelandic actor. He is known for his role as Móri in Life in a Fishbowl. In 2015 he won an Edda Award for that same role.

Bachmann grew up in the Fossvogur area of Reykjavík, Iceland before moving to Breiðholt when he was 10 years old. He did not do well in school in the early years. Looking back he remembers, that he was barely able to read or write before changing schools from Fossvogur to the one in Breiðholt. Bachmann graduated from the Icelandic Drama School in 1991. Since graduation he has worked with theatre groups in Reykjavík and Akureyri and was president of the latter for a few years. He has held many acting courses, and has served as a teacher at both the Icelandic Drama School and the Icelandic Film School. In 2013 he worked with the National Theatre of Iceland. Before every premiere Bachmann goes to the gym, goes swimming and finishes off with a sauna. "This is something I've always done and goes with every film or stage premiere".