Cognomen Þorbjörg (Þorbjörg 
) , throughout the world, is an extremely rare last name. Much more frequently, Þorbjörg is the forename as well as the last name.
Hall, Garðarsdóttir, Gísladóttir, Jóhannsdóttir, Hólmgeirsdóttir, Friðriksdóttir, Kjartansdóttir, Davíðsdóttir, Pétursdóttir, Gunnarsdóttir, Guðmundsdóttir, Halldórsdóttir, Ásgeirsdóttir, Sigurðardóttir, Kristinsdóttir, Ragnarsdóttir, Björnsdóttir, Sævarsdóttir, Ólafsdóttir, Bakke, Tobba, Gígja, Skúladóttir, Jónsdóttir, Harðardóttir, Magnúsdóttir, Skagfjörð, Sveinsdóttir, Snorradóttir, Auðunsdóttir, Karlsdóttir, Guðnadottir, Guðnadóttir, Árnadóttir, Kristjánsdóttir, and Þórarinsdóttir