In the fictional Star Wars universe, Darth precedes the title of a Sith Lord.

Contrary to popular belief, the word "Darth" is neither a Dutch nor German word meaning "dark" (donker and dunkel, respectively). Also, Darth is often thought to be a combination of letters from the title 'Dark Lord of the Sith', but there is no basis in Star Wars canon for this. "Darth" may also be a portmanteau of "dark" and "death".

The term first appeared in the original script for Star Wars IV: A New Hope, which bore little resemblance to the final release of the film. In it, a "Darth Vader" appeared as an Imperial official who would be renamed Grand Moff Tarkin in the final film, with Darth Vader becoming the name of the menacing black-armored villain.

Sith Lords who have held the title include Darth Revan, Darth Malak, Darth Bandon, Darth Nihilus, Darth Traya, Darth Sion, Darth Andeddu , Darth Rivan , Darth Bane, Darth Plagueis, Darth Sidious, Darth Maul, Darth Tyranus, and Darth Vader.

Since the popularity of Star Wars, the term Darth has really entered the popular lexicon as a term for evil. Most references are still associated with the Star Wars universe.