Koyuki (小雪; full name Koyuki Katō [加藤小雪] (born 18 December 1976), is a Japanese model and actress.

Koyuki was born in Zama, Kanagawa-ken. She started her model career in 1995 and has since starred in various Japanese dramas, TV and magazine ad campaigns and films. She frequently appears in Japanese print and television marketing campaigns for electronics company Panasonic. Her first, and to date only, international film was The Last Samurai where she played Taka, the wife of a Samurai slain by the character played by Tom Cruise, Nathan Algren. She will be in the upcoming Blood: The Last Vampire live-action starring Jun Ji-Hyun.

Gaining her first exposure to Western audiences in Edward Zwick's 2003 film Last Samurai, The (2003), Koyuki was well-known in Japan for years before that. She first caught the attention of the public in 1997 by winning an exclusive modelling contract with the magazine Non-no, but quickly grew beyond modelling and has earned acclaim as an actress through her many roles on Japanese television and in several Japanese films.