Conspiracy, besides its ordinary meaning (see conspiracy), means:

• Conspiracy theory, a theory that defies common historical or current understanding of events, under the claim that those events are the result of manipulations by one or more secretive powers.
• Conspiracy, an album by a heavy metal group called King Diamond.
• Conspiracy, the name of an episode of Star Trek: The Next Generation.
• Conspiracy (TV movie), the name of a television film about the Wannsee conference.
• Conspiracy, a hungarian demogroup.
• The Great Conspiracy, a barbarian assault on Roman Britain