Cyteen (1988) is a science fiction novel by American writer C. J. Cherryh, set in her Alliance-Union universe. The murder of a major Union politician and scientist has deep, long-lasting repercussions. It won the Hugo Award for Best Novel in 1989.

Carolyn Janice Cherry, better known by the pen name C. J. Cherryh, is an American writer of speculative fiction. She has written more than 80 books since the mid-1970s, including the Hugo Award–winning novels Downbelow Station (1981) and Cyteen (1988), both set in her Alliance–Union universe, and her Foreigner series. She is known for worldbuilding, depicting fictional realms with great realism supported by vast research in history, language, psychology, and archeology.