Sigurd I Magnusson (c. 1090 – 26 March 1130), also known as Sigurd the Crusader, is King of Norway from 1103 to 1130.

His rule, together with his brother Eystein I of Norway (until Eystein dies in 1123), has been regarded by historians as a golden age for the medieval Kingdom of Norway.

He is otherwise famous for leading the Norwegian Crusade (1107–1110), earning the eponym "the Crusader".