In Finnish mythology and the mythology of Lapland, Louhi is a queen of the land known as Pohjola. She is described as a powerful witch with the ability to change shape and weave mighty enchantments. She is also the main opponent of Väinämöinen and his group in the battle for the magical artifact Sampo in the Kalevala. She has a number of beautiful daughters, whom Ilmarinen, Lemminkäinen and other heroes attempt to win in various legends. Louhi, in true fairy tale form, sets them difficult to impossible tasks to perform in order to claim such a prize.

As many mythological creatures and objects are easily conflated and separated in Finnish mythology, Louhi is probably an alter-ego of various other goddesses, notably Louhetar, Loviatar, Lovitar.

"Louhi" or "lovi" also refer to a state of trance, or of magic. This can be seen, for example, in the opening lines often-used in spells that go "Nouse luontoni lovesta, haon alta haltiani" or variations thereof, translatable to "rise my nature from the lovi, (rise) my spirit from beneath the threshold".