Doomsday Machine may refer to:

• Doomsday device, a hypothetical weapon which could destroy all life on the Earth
• Doomsday Machine (film), a 1972 science-fiction film
• The Doomsday Machine (book), a 2012 non-fiction book arguing that nuclear energy is a kind of 'Doomsday' strategy
• "The Doomsday Machine" (Star Trek: The Original Series), a 1967 episode of Star Trek: The Original Series
• Doomsday Machine (album), a 2005 album by melodic death metal band Arch Enemy
• The Doomsday Machine: Confessions of a Nuclear War Planner (2017), book by Daniel Ellsberg