"The Third Kryptonian" is a three-issue Superman comic book story arc written by Kurt Busiek with art by Rick Leonardi.
The story arc appears in Superman #668-670, and is rooted in a three-part story arc that was released between "Superman: Up, Up and Away!" and "Last Son" called "Back in Action", in which a villain named the Auctioneer captures people as trophies until Superman and an alliance of heroes and villains unites to stop him. The Auctioneer discloses that he came looking for the "third Kryptonian", a comment that confuses Superman. Although the third Kryptonian may have been Chris Kent, this was revealed not to be the case.
The story in Superman #670 was slated to appear in the Superman Annual #13.