Harald Gylle (1103–1136), king of Norway, was born in Ireland. His byname Gylle is probably from Gylle Krist, i.e. servant of Christ.

Around 1127, he went to Norway and declared he was a son of King Magnus Barefoot, who had visited Ireland just before his death in 1103, and consequently a half-brother of the reigning king, Sigurd.

He appears to have submitted successfully to the ordeal of fire, and the alleged relationship was acknowledged by Sigurd on condition that Harald did not claim any share in the government of the kingdom during his lifetime or that of his son Magnus. Living on friendly terms with the king, Harald kept this agreement until Sigurd’s death in 1130. Then war broke out between himself and Magnus, and after several battles the latter was captured in 1135, his eyes were put out, and he was thrown into prison.

Harald now ruled the country until 1136, when he was murdered by Sigurd Slembedjakn , another bastard son of Magnus Barefoot.

Harald was married to Ingrid Ragnvaldsdottir , and had the son Inge with her. He also had sons with other women: Sigurd, Eystein and Magnus. All four sons were subsequently kings of Norway.