The T-X is the name of a fictional cyborg assassin who appears in the Terminator franchise. The T-X model is a gynoid assassin and infiltrator. The character was introduced as the main antagonist in the 2003 film Terminator 3: Rise of the Machines, portrayed by Kristanna Loken. T-X has the ability to assume the appearance of other characters. This ability to shapeshift is similar to that of the T-1000, the main antagonist of Terminator 2: Judgment Day. T-X also has the ability to scan DNA from blood samples it puts on its tongue.

Terminator 3: Rise of the Machines is a 2003 science fiction action film that is the third installment in the Terminator franchise and a sequel to Terminator 2: Judgment Day (1991). It is directed by Jonathan Mostow and stars Arnold Schwarzenegger, Nick Stahl, Claire Danes, and Kristanna Loken. In its plot, the malevolent artificial intelligence Skynet sends a T-X (Loken)—a highly advanced Terminator—back in time to ensure the rise of machines by killing top members of the future human resistance as John Connor's (Stahl) location is unknown. The resistance sends back a reprogrammed T-850 (Schwarzenegger) to protect John and Kate (Danes).