Kristin Sigurdsdatter (ca. 1125–1178) was a Norwegian princess and mother of King Magnus V of Norway.^[1]

Kristin was a daughter of King Sigurd I of Norway and Malmfred of Kiev. She married Erling Skakke (Erling Ormsson Skakke), a Norwegian nobleman who had earned his reputation crusading with Rögnvald Kali Kolsson, the Earl of Orkney.^[2][3] They had a son, Magnus Erlingsson.

Kristin was the only legitimate child of King Sigurd. In 1130, King Sigurd died with no legitimate sons. An illegitimate son, Magnus Sigurdsson (Magnus 4 Sigurdsson Blinde), became king of Norway jointly with his uncle Harald Gille. Harald Gille had four sons, Inge, Eystein, Sigurd and Magnus Haraldsson, all of whom became kings of Norway.^[4][5]

Following the death of King Inge in 1161, Kristin's son Magnus was crowned king at the age of eight. He ruled as king of Norway until his death in 1184.^[6]