Seven of Nine is a fictional character introduced in the American science fiction television series Star Trek: Voyager. Portrayed by Jeri Ryan, she is a former Borg drone who joins the crew of the Federation starship Voyager. Her full Borg designation was Seven of Nine, Tertiary Adjunct of Unimatrix Zero One. While her birth name became known to her crewmates, after joining the Voyager crew she chose to continue to be called Seven of Nine, though she allowed "Seven" to be used informally.

Star Trek: Voyager is an American science fiction television series created by Rick Berman, Michael Piller and Jeri Taylor. It originally aired from January 16, 1995, to May 23, 2001, on UPN, with 172 episodes over seven seasons. It is the fifth series in the Star Trek franchise. Set in the 24th century, when Earth is part of a United Federation of Planets, it follows the adventures of the Starfleet vessel USS Voyager as it attempts to return home to the Alpha Quadrant after being stranded in the Delta Quadrant on the far side of the galaxy.