The terms Jötunheimr (in Old Norse orthography: Jǫtunheimr [ˈjɔtonˌhɛimz̠]; often anglicised as Jotunheim) or Jötunheimar refer to either a land or multiple lands respectively in Nordic mythology inhabited by the jötnar (relatives of the gods, in English sometimes inaccurately called "giants").

Jötunheimar are typically, but not exclusively, presented in Eddic sources as prosperous lands located to the north and are commonly separated from the lands inhabited by gods and humans by barriers that cannot be traversed by usual means.

Old Norse: Jǫtunheimr is a compound word formed from Old Norse: 'jǫtunn' and 'heimr', meaning a 'home' or 'world'. When attested in Eddic sources, the word is typically found in its plural form, Jǫtunheimar ('jǫtunn-lands').

Jötunheimar are mentioned in three poems of the Poetic Edda. In the beginning of Völuspá, the coming of three women out of Jötunheimar marks the end of the Age of Gold for the gods. Towards the end of the poem, in the section describing the onset of Ragnarök, they are mentioned as follows:

In the prose prologue Skírnismál, while sitting on Hliðskjálf, Freyr sees Gerðr, the daughter of Gymir, in Jötunheimar and falls in love with her. A further prose section then describes that he gives his servant Skírnir his horse and sends him to her home at Gymisgarðar in Jötunheimar, which he reaches after travelling through wet mountains, a flickering flame and darkness. After his journey, Skírnir meets Gerðr and her family living in a hall and tending to animals in the daylight, protected by a fence and dogs. Upon his return, Freyr asks in a stanza of the tidings from Jötunheimar, to which his servant replies that she will meet him in nine nights at Barri.

In Þrymskviða, Loki uses Freyja's fjaðrhamr to fly to Þrymr's home in jötunheimar to find Thor's hammer. The jötunn tells the god that he will only return the hammer in exchange for Freyja's hand in marriage. When she refuses to go to jötunheimar, Thor goes in her place, disguised in a wedding veil, with Loki as his handmaid. In this account, Þrymr's estate is presented as wealthy, with him holding dogs on golden leashes and telling that has cattle with golden horns in his stables and many jewels, with Freyja being the only thing he lacked.

Jötunheimar are referenced throughout Gylfaginning such as when Gefjun takes four oxen, who were her sons with a jötunn, out of the jötunheimar to the north and uses them to plough land out of Sweden, forming Zealand. Jötnar and gýgjar are also described as living in jötunheimar such as the father of Night, Narfi and Angrboða, the mother of Fenrir. Beings may also come out from Jötunheimar to interact with others, such as the wright who, with the help of his horse Svaðilfari, builds fortifications for the gods to protect them from jötnar.

Skáldskaparmál tells of how Loki was once coerced into helping the jötunn Þjazi abduct Iðunn who carried her northwards, back to his home in Jötunheimar named Þrymheimr. Using Freyja's fjaðrhamr, Loki became a hawk and flew to Þjazi's home while the jötunn was away, having rowed out to sea. Upon reaching Iðunn, Loki turned her into a nut and flew away with her in his talons. Þjazi later finds out that Iðunn is gone and he chases after them as an eagle, but is killed as he reached Asgard when he flies into a fire that the gods made.