Haakon Haakonsson the Young (Norwegian: Håkon Håkonsson Unge, Old Norse: Hákon Hákonarson hinn ungi) (10 November 1232 – 5 May 1257) was the son of king Haakon Haakonsson of Norway, and held the title of king, subordinate to his father, from 1 April 1240 to his death.

This marked a break with older traditions, when the question of legitimacy of birth was not of consequence in inheriting the kingdom.

Rikitsa was a daughter of Sweden's de facto ruler, Jarl Birger Magnusson, and sister of the underage king Valdemar Birgersson.

The marriage was a result of diplomatic efforts by king Haakon the Old to forge an alliance between Norway and Sweden, primarily directed against Denmark.

Haakon the Young took part in his father's military operations against Denmark in 1256 and 1257, when the Norwegian kings ravaged the Danish province of Halland.

The saga describes Haakon the Young as "of somewhat over medium height, well-shaped, handsome of countenance, with pretty hair and beautiful eyes.

He does not seem to have been considered an heir to the throne, as Haakon the Young's younger brother, Magnus, was hailed as king already in 1257.