Spock is a fictional character in the Star Trek media franchise. He first appeared in the original Star Trek series serving aboard the starship USS Enterprise as science officer and first officer and later as commanding officer of the vessel. Spock's mixed human–Vulcan heritage serves as an important plot element in many of the character's appearances. Along with Captain James T. Kirk and Dr. Leonard "Bones" McCoy, he is one of the three central characters in the original Star Trek series and its films. After retiring from active duty in Starfleet, Spock served as a Federation ambassador, and later became involved in the ill-fated attempt to save Romulus from a supernova, leading him to live out the rest of his life in a parallel universe.

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.