Gunther (Gundahar, Gundahari, Latin Gundaharius, Gundicharius, or Guntharius, Old English Guðhere, Old Norse Gunnarr, anglicised as Gunnar) is the German name of a semi-legendary king of Burgundy of the early 5th century. Legendary tales about him appear in Latin, medieval Middle High German, Old Norse, and Old English texts, especially concerning his relations with Siegfried (Sigurd in Old Norse) and his death by treachery in the hall of Attila the Hun.

Günther or Gunther and variants, Günter or Gunter, are Germanic names derived from Gunthere, Gunthari, composed of "battle" (Old Norse gunnr) and heri, hari "army".