In the Hall of the Mountain King (Norwegian: I Dovregubbens hall) is a piece of orchestral music composed by Edvard Grieg for the sixth scene of Act II in Henrik Ibsen's play Peer Gynt, which premiered in Christiania on February 24, 1876.

It was originally part of Opus 23, but was later extracted as the final piece of Peer Gynt, Suite No. 1, Op. 46. Although a performance of the full piece runs to slightly less than 3 minutes, its easily recognizable theme has helped it attain iconic status in popular culture, where it has been arranged by many artists.

The piece is played as the eponymous Peer Gynt, in a dream-like fantasy, enters "the royal hall of the Old Man of the Dovrë (the Mountain King)." The scene's introduction continues: "There is a great crowd of troll courtiers, gnomes and goblins. The Old Man sits on his throne, with crown and sceptre, surrounded by his children and relatives. Peer Gynt stands before him. There is a tremendous uproar in the hall." The lines sung are the first lines in the scene.