In Norse mythology, Valhalla (/vælˈhælə/ val-HAL-ə, US also /vɑːlˈhɑːlə/ vahl-HAH-lə; Old Norse: Valhǫll [ˈwɑlhɒlː], lit. 'Hall of the Slain') is described as a majestic hall located in Asgard and presided over by the god Odin. There were five possible realms the soul could travel to after death. The first was Fólkvangr, ruled by the goddess Freyja. The second was Hel, ruled by Hel, Loki's daughter. The third was that of the goddess Rán. The fourth was the Burial Mound where the dead could live. The fifth and last realm was Valhalla, ruled by Odin and was called the Hall of Heroes. The masses of those killed in combat (known as the einherjar), along with various legendary Germanic heroes and kings, live in Valhalla until Ragnarök, when they will march out of its many doors to fight in aid of Odin against the jötnar. Valhalla was idealized in Viking culture and gave the Scandinavians a widespread cultural belief that there is nothing more glorious than death in battle. The belief in a Viking paradise and eternal life in Valhalla with Odin may have given the Vikings a violent edge over the other raiders of their time period.

Valhalla is attested in the Poetic Edda, compiled in the 13th century from earlier traditional sources, in the Prose Edda (written in the 13th century by Snorri Sturluson), in Heimskringla (also written in the 13th century by Snorri Sturluson), and in stanzas of an anonymous 10th-century poem commemorating the death of Eric Bloodaxe known as Eiríksmál as compiled in Fagrskinna. Valhalla has inspired innumerable works of art, publication titles, and elements of popular culture and is synonymous with a martial (or otherwise) hall of the chosen dead. The name is rendered in modern Scandinavian languages as Valhöll in Icelandic, while the Swedish and Norwegian form is Valhall; in Faroese it is Valhøll, and in Danish it is Valhal.

The Modern English noun Valhalla derives from Old Norse Valhǫll, a compound noun composed of two elements: the masculine noun valr 'the slain' and the feminine noun hǫll which originally referred to a rock, rocks, or mountain; not a hall, thus meaning Valhalla was originally understood as the "rock of the Slain". The form "Valhalla" comes from an attempt to clarify the grammatical gender of the word. Valr has cognates in other Germanic languages such as Old English wæl 'the slain, slaughter, carnage', Old Saxon wal-dād 'murder', Old High German 'battlefield, blood bath'. All of these forms descend from the Proto-Germanic masculine noun *walaz. Among related Old Norse concepts, valr also appears as the first element of the noun valkyrja 'chooser of the slain, valkyrie'.

The second element, hǫll, is a common Old Norse noun. It is cognate to Modern English hall and offers the same meaning. Both developed from Proto-Germanic *xallō or *hallō, meaning 'covered place, hall', from the Proto-Indo-European root *kol-. As philologists such as Calvert Watkins note, the same Indo-European root produced Old Norse hel, a proper noun employed for both the name of another afterlife location and a supernatural female entity as its overseer, as well as the modern English noun hell. In Swedish folklore, some mountains traditionally regarded as abodes of the dead were also called Valhall. According to many researchers^[who?], the hǫll element derives from hallr, "rock", and referred to an underworld, not a hall.

Valhalla is referenced at length in the Poetic Edda poem Grímnismál, and Helgakviða Hundingsbana II, while Valhalla receives lesser direct references in stanza 32 of the Völuspá, where the god Baldr's death is referred to as the "woe of Valhalla", and in stanzas 1 to 3 of Hyndluljóð, where the goddess Freyja states her intention of riding to Valhalla with Hyndla, in an effort to help Óttar, as well as in stanzas 6 through 7, where Valhalla is mentioned again during a dispute between the two.

In stanzas 8 to 10 of Grímnismál, the god Odin (in the guise of Grímnir) proclaims Valhalla is in the realm of Glaðsheimr. Odin describes Valhalla as shining and golden, and it "rises peacefully" as seen from afar. From Valhalla, every day Odin chooses from those killed in combat. Valhalla has spear-shafts for rafters, a roof thatched with shields, coats of mail are strewn over its benches, a wolf hangs in front of its west doors, and an eagle hovers above it.

 The hall is easily recognised by those who come to Óðinn:
 Spear-shafts are the rafters, the hall is thatched with shields,
 And the benches are strewn with byrnies.

 The hall is easily recognised by those who come to Óðinn:
 A warg hangs before the western door,
 And an eagle hovers above . . .

 Andhrímnir lets Saehrímnir, best of flesh,
 Be seethed in Eldhrímnir, the cauldron,
 Though few know what the Einherjar feast on.

 Battle-accustomed, glorious Host-Father feeds Geri and Freki;
 But weapon-stately Óðinn lives on wine alone.

 Huginn and Muninn fly over the mighty earth every day;
 I fear for Huginn, that he not come back,
 But I look more for Muninn.

 Thundr roars loudly;
 Thjóðvitnir’s fish sports in the flood;
 The river roars loudly,
 The battle-slain think it too strong to wade.

 That which stands on the holy fields,
 Before the holy doors,
 Is called Valgrind, the Slain-Gate;
 Those gates are old,
 And few know how they may be locked.

 Five hundred and forty doors:
 So I know to be in Valhöll;
 Eight hundred Einherjar go out of one door,
 When they fare to battle the Wolf.

 The goat who stands on Host-Father’s hall
 Is called Heiðrún,
 And bites off the limbs of Laeraðr;
 She shall fill a cauldron with the shining mead,
 That drink will never be exhausted.

 The hart who stands on Host-Father’s hall
 Is called Eikthyrnir,
 And bites off the limbs of Laeraðr;
 And drops fall from his horns into Hvergelmir,
 To which all waters wend their way.

 Shaker and Mist I wish to have bear a horn to me;
 Skeggjöld and Striker, Shrieker and Battle-Fetter,
 Loudness and Spear-Striker, Shield-Strength and Rede-Strength,
 And God-Inheritance,
 They bear ale to the Einherjar.
(Grímnismál 9–10, 18–22, 23–26)

Odin, throughout this story is seen to have pet ravens that he sends out, and the warriors of his hall are dead men and ghosts who endlessly fight battles and endlessly die. There are also women who feed them and serve them alcohol and are the same spirits who chose them to die in the battles they fight. Valhalla in this story can be seen as a beautiful hall for the dead but it can also be seen as a lofty stylization of a battlefield after a fight. There are broken weapons and shields and dead bodies and ghosts cover the hall that gets ravaged by wolves and ravens. To the Vikings of the time, this was not only their desired afterlife, but a way to cope with the horrors of battle.