C-3PO ( 3PO or Threepio for short) is a robot character from the Star Wars universe who appears in both the original Star Wars films and the prequel trilogy. He is also a major character in the television show Droids, and appears frequently in the series' "Expanded Universe" of novels, comic books, and video games. Along with Anakin Skywalker (Darth Vader), Obi-Wan Kenobi and R2-D2, he is one of only four characters to appear in all six Star Wars films. C-3PO (played by Anthony Daniels) and R2-D2 (played by Kenny Baker) are the only characters portrayed by the same actor in all six films.

C-3PO is a protocol droid designed to serve humans, and boasts that he is fluent in "over six million forms of communication". He is generally seen with his long-time counterpart, R2-D2. Threepio's main function is to assist etiquette, customs, and translation, so that meetings of different cultures run smoothly. Threepio and R2-D2 played a vital and pivotal role in the Galaxy's history needed. While many protocol/interpretor droids range in color, C-3PO's own identifying colors are primarily gold with silver from the right knee down.