In J. R. R. Tolkien's fictional universe of Middle-earth, Mount Doom, or Orodruin, is a volcano in Mordor where the One Ring was forged in the Crack of Doom, a fiery chasm within the mountain. Frodo's quest to destroy the Ring at Mount Doom occupies the bulk of The Lord of the Rings.

Orodruin is Sindarin for "Fire Mountain". The Sindarin equivalent of Mount Doom is Amon Amarth, meaning "Mountain of Fate".