Defiant could refer to:
- One of the various Federation starships of that name:
- USS Defiant (NCC-1764), a Constitution-class starship
- USS Defiant (2370), lead ship of the class, the first Defiant-class starship to bear the name
- USS Defiant (2375), the second Defiant-class starship to bear the name (formerly the USS Sao Paulo)
- The ISS Defiant, a Terran Rebellion starship from the 24th century mirror universe
- HMS Defiant, The British Royal Navy ship
- The Template:ShipClass escort, a Federation starship type
- "Defiant", a Season Three episode of Star Trek: Deep Space Nine
Regardless - all Defiant-class starships had temporal shielding.
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