Thorfinn may refer to:
- Thorfinn Turf-Einarsson, Earl of Orkney (Thorfinn Skullsplitter) (floruit 10th century)
- Thorfinn Sigurdsson, Earl of Orkney (Thorfinn the Mighty) (floruit early 11th century)
- Thorfinn Karlsefni, Icelandic explorer (died circa 1010)
- Thorfinn of Hamar, Christian bishop and saint