Thorfinn Karlsefni or Þorfinnur Karlsefni was an Icelandic explorer who led an attempt to settle Vinland shortly after 1000 A.D.

Also among about 160 settlers was Freydís Eiríksdóttir and Thorvald Eriksson, half-sister and brother of Leif Eriksson.

In the early 20th century, Einar Jonsson, an Icelandic sculptor, created a statue of Thorfinn Karlsefni which was placed in Philadelphia, Pennsylvania.