"The Devil in the Dark" is the twenty-fifth episode of the first season of the American science fiction television series Star Trek. Written by Gene L. Coon and directed by Joseph Pevney, the episode first aired on March 9, 1967.

Star Trek is an American science fiction television series created by Gene Roddenberry that follows the adventures of the starship USS Enterprise (NCC-1701) and its crew. It acquired the retronym of Star Trek: The Original Series (TOS) to distinguish the show within the media franchise that it began.