The Sith are the main antagonists of many works in the fictional universe of the Star Wars franchise. The Sith Order are depicted as an ancient monastic and kraterocratic cultist organization of supernaturally gifted Force-wielders driven by a machiavellian–imperialist agenda of galactic domination and revenge against their arch-rivals, the Jedi Order. The various villainous groups in the franchise, namely the Separatist Alliance, the First Galactic Empire, the Imperial Remnant, and the First Order, all originated, either directly or indirectly, from the Sith.

Sith deal in absolutes; they view the world as «either with them, or against them.» Sith are the most powerful and deadly practitioners of the dark side of the Force, given their intrinsic aptness for treachery, goals of galactic domination, and philosophical belief in personal freedom at all costs. They are ruthless and totalitarian by design, in which a supreme autocratic authority is concentrated in a single individual granted the honorific Dark Lord of the Sith. Sith culture is of perpetual self-destruction and reinvention; transfer of power is conducted through state-sanctioned assassinations: when a Sith Lord grows complacent and begins to show weakness, they are eventually killed and their property and authority transferred to the apprentice who killed them. Robberies, betrayal, and sabotage are commonplace; murder is acceptable so long as the culprit is not caught. Sith teach their apprentices to revere the dark side of the Force and to believe that the galaxy was theirs to rule by cosmic right. This kraterocratic system ensures that Sith society nurtures some of the most vicious and competitive individuals in the galaxy and is only governed by those strong enough to seize control.