Sigurd II (1133–1155) was the son of Harald Gille, king of Norway and his mistress Tora Guttormsdottir .

Sigurd grew up in Trøndelag, and was made king there in 1136 upon the murder of his father, King Harald, together with his younger brother Inge. During their minority, the Norwegian nobility cooperated to rule the kingdom and advice the kings.

The early years of Sigurd's regin was dominated by battles against the pretenders Sigurd Slembedjakn and Magnus the Blind. These two were finally defeated and slain in a battle at Hvaler in 1139.

After this followed a period of peace. In 1142, their brother Eystein came to Norway from Ireland. His parentage was accepted, since Harald Gille had acknowledged that he had a son in Ireland. Eystein thus became co-king together with Sigurd and Inge.

In 1152, Norway was visited by the papal legate Nicholas Breakspear. During his visit, the church in Norway was organised into one archbisopric, with its seat at Nidaros.

As they grew up, and their old advisors died, hostility began to grow among the brothers. In 1155, all three of them met at Bergen in an effort to keep the peace. Inge claimed Sigurd and Eystein for planning to have him dethroned. Sigurd denied the accusations, but a few days later one of Inge's guards was killed by one of Sigurd's. At the advice of his mother Ingrid and his senior advisor, Gregorius Dagsson , Inge ordered his men to assault the house where Sigurd was residing. Sigurd had but few men, and no mercy was given. King Sigurd fell on 6 February 1155.

After his death, Sigurd's supporters took his son Håkon Herdebrei as king.

During the following civil war, many royal pretenders claimed to be the son of King Sigurd. This was mostly a political statement, and their claims were at best dubious. Sverre Sigurdsson was the most successful by far of these claimants, and eventually succeeded in becoming king of Norway.