Hákonar saga Hákonarsonar (The Saga of Haakon Haakonarson) or Hákonar saga gamla Hákonarsonar is an Old Norse Kings' Saga, telling the story of the life and reign of King Haakon Haakonarson of Norway.
The circumstances of the saga's composition are exceptionally well understood, as they are recorded in some detail in Sturlunga saga (particularly Sturlu þáttr): the saga was written in the 1260s (apparently 1264-65) by the Icelandic historian and chieftain Sturla Þórðarson (nephew of the noted historian Snorri Sturluson). Sturla Þórðarson was at the court of Haakon's son Magnus Lagabøte when Magnus learned of his father's death in Kirkwall in Orkney. Magnus is said to have immediately commissioned Sturla to write his father's saga. This was awkward for Sturla: 'King Hákon had instigated the death of Sturla's uncle, Snorri Sturluson, in 1241. Sturla rightly regarded Hákon as his most dangerous enemy, for he had steadfastly resisted the king's subjugation of Iceland to Norway, which was accomplished in 1262-1264. Skúli Bárðarson (d. 1240), Hákon's most dangerous rival for royal power, was the maternal grandfather of Magnús, who supervised the composition of his father's biography, much as King Sverrir is said to have "sat over" Karl Jónsson as the Icelandic abbot wrote Sverrir's biography'.
The saga is the main source to Norwegian history for the period from 1217 (Haakon's accession) to his death in 1263. Additionally the saga also describes events in Iceland and other locations where Haakon's realm had a presence.
'Because Sturla relied heavily on eyewitness accounts and written documentation as sources for the prose account of Hák[onar saga], the poetic citations in the saga are mainly ornamental in nature. The inclusion of the stanzas reflects the convention in the earlier kings’ sagas of using skaldic stanzas to verify the events described in the prose texts.' Nevertheless, the saga contains lots of verse, much by Sturla himself, along with some poetry by his brother Óláfr hvítaskáld Þórðarson and his uncle Snorri Sturluson, Gizurr Þorvaldsson’s Hákonardrápa, and numbers of lausarvísur (mostly attributed but in three cases anonymous).