In Norse mythology, Freyja (Old Norse "(the) Lady") is a goddess associated with love, beauty, fertility, sex, war, gold, and seiðr (magic for seeing and influencing the future). Freyja is the owner of the necklace Brísingamen, rides a chariot pulled by two cats, is accompanied by the boar Hildisvíni, and possesses a cloak of falcon feathers to allow her to shift into falcon hamr. By her husband Óðr, she is the mother of two daughters, Hnoss and Gersemi. Along with her twin brother Freyr, her father Njörðr, and her mother (Njörðr's sister, unnamed in sources), she is a member of the Vanir. Stemming from Old Norse Freyja, modern forms of the name include Freya, Freyia, and Freja.

Freyja rules over her heavenly field, Fólkvangr, where she receives half of those who die in battle. The other half go to the god Odin's hall, Valhalla. Within Fólkvangr lies her hall, Sessrúmnir. Freyja assists other deities by allowing them to use her feathered cloak, is invoked in matters of fertility and love, and is frequently sought after by powerful jötnar who wish to make her their wife. Freyja's husband, the god Óðr, is frequently absent. She cries tears of red gold for him, and searches for him under assumed names. Freyja has numerous names, including Gefn, Hörn, Mardöll, Sýr, Vanadís, and Valfreyja.

Freyja is attested in the Poetic Edda, compiled in the 13th century from earlier traditional sources; in the Prose Edda and Heimskringla, composed by Snorri Sturluson in the 13th century; in several Sagas of Icelanders; in the short story "Sörla þáttr"; in the poetry of skalds; and into the modern age in Scandinavian folklore.

Scholars have debated whether Freyja and the goddess Frigg ultimately stem from a single goddess common among the Germanic peoples. They have connected her to the valkyries, female battlefield choosers of the slain, and analyzed her relation to other goddesses and figures in Germanic mythology, including the thrice-burnt and thrice-reborn Gullveig/Heiðr, the goddesses Gefjon, Skaði, Þorgerðr Hölgabrúðr and Irpa, Menglöð, and the 1st century CE "Isis" of the Suebi. In Scandinavia, Freyja's name frequently appears in the names of plants, especially in southern Sweden. Various plants in Scandinavia once bore her name, but it was replaced with the name of the Virgin Mary during the process of Christianization. Rural Scandinavians continued to acknowledge Freyja as a supernatural figure into the 19th century, and Freyja has inspired various works of art.

The name Freyja transparently means 'lady, mistress' in Old Norse. Stemming from the Proto-Germanic feminine noun *frawjōn ('lady, mistress'), it is cognate with Old Saxon frūa ('lady, mistress') or Old High German frouwa ('lady'; cf. modern German Frau). Freyja is also etymologically close to the name of the god Freyr, meaning 'lord' in Old Norse. The theonym Freyja is thus considered to have been an epithet in origin, replacing a personal name that is now unattested.

In addition to Freyja, Old Norse sources refer to the goddess by the following names:

In the Poetic Edda, Freyja is mentioned or appears in the poems Völuspá, Grímnismál, Lokasenna, Þrymskviða, Oddrúnargrátr, and Hyndluljóð.

Völuspá contains a stanza that mentions Freyja, referring to her as "Óð's girl"; Freyja being the wife of her husband, Óðr. The stanza recounts that Freyja was once promised to an unnamed builder, later revealed to be a jötunn and subsequently killed by Thor (recounted in detail in Gylfaginning chapter 42; see Prose Edda section below). In the poem Grímnismál, Odin (disguised as Grímnir) tells the young Agnar that every day Freyja allots seats to half of those that are slain in her hall Fólkvangr, while Odin owns the other half.