Gjallarhorn refers to both a musical instrument and a drinking horn in Norse mythology.
Gjallarhorn may also refer to: Gjallarhorn (band), a Swedish language folk music band from Finland Gjallarhorn (album), 2005 album by Japanese band 9mm Parabellum Bullet Gjallarhorn, magazine published by the National Socialist Movement of Norway Gjallarhorn, fictional organization in the anime series Mobile Suit Gundam: Iron-Blooded Orphans Gjallarhorn, an exotic rocket launcher from the game Destiny Gjallarhorn (album), a 2017 album but Danheim for the single album Gjallarhorn (song), a song by Danheim from his album Munarvágr