In Norse mythology, Brünnehilde was a shieldmaiden and a Valkyrie. In the southern version of the Nibelungenlied legend, she was ordered to decide a fight in favor of the older of two kings. The valkyrie knew that Odin himself preferred the young king, Sigmund, yet Frigga demanded his death for fathering a son by his own twin sister, Siglind. Brünnehilde decided the battle for Sigmund and saves his young wife, who was pregnant with a son. For this Odin condemned the valkyrie to live the life of a mortal woman and cursed her to sleep until any man would rescue and marry her. Brünnehilde begged Odin to change this, reminding him that she had only done what the god had secretly wanted, and she convinced him to allow only the best hero to rescue her. Accordingly, Brünnehilde was imprisoned in a ring of fire the only the greatest hero could enter. Sigurd, the son of Sigmund, entered that ring after killing the dragon Fafnir and awoke Brünnehilde. Sigurd gave her his ring, Andvarinaut, unaware that it was cursed and she pledges herself to him, despite her prophecies regarding his doom and his marriage to another.

Siegfried duly betrayed her and married Gudrun when bewitched by the sorceress Grimhild to forget Brünnehilde. Gudrun's brother, Gunnar, then sought to court Brünnehilde but was stopped by the ring of fire that still surrounded her. Sigurd exchanged shapes with him and entered the ring of fire a second time. Gunnar and Brünnehilde married, but she plotted revenge for the deception and betrayal she had suffered. Her brother-in-law Guttorm killed Sigurd, Brünnehilde herself killed Sigurd's three-year-old son, and then she willed herself to die.

According to other sagas, Brünnehilde bore Sigurd a daughter, Aslaug, who later married Ragnar Lodbrok.

The role of Brünnehilde in the Nibelungenlied appears to have been influenced by Brunhilda, the historical queen of Austrasia. The history of Brunhilda and her husband Sigebert I includes fratricide, a long battle between brothers, and dealings with the Huns.

Other names

• Brunhild
• Brunhilde
• Brunhilt
• Brunnehilde
• Brünnehilde
• Brynhild
• Brynhilt

123 Brunhild is an asteroid.