Sayoko Yamaguchi (Japanese: 山口小夜子, September 19, 1949 – August 14, 2007) was a Japanese model and actress.

Yamaguchi was born in Yokohama and graduated from Sugino Gakuen's Dressmaker Gakuin design school in Tokyo.^[1]

Yamaguchi broke into the international modeling industry in the 1970s.^[2] She was one of the first asian models to be featured in the world's top fashion shows and magazines. She made her debut in Paris in 1972,^[2] and went on to work in New York City and other international cities.

In 1977 Newsweek named her one of the world's top six fashion models.^[1][2] Also that year, she was featured on the cover of Steely Dan's Aja album, photographed by Hideki Fujii.^[3]

Yamaguchi went on to continue her career as a film and theater actress, as well as a costume designer.^[2]

Yamaguchi died aged 57, on August 14, 2007, of acute pneumonia.^[2] In 2015 she was the subject of a posthumous documentary, Kōri no hanabi Sayoko Yamaguchi (Ice Fireworks Sayoko Yamaguchi).^[4]

• Carol (1974, documentary) – Self
• ピーターソンの鳥 (Peterson's Bird) (1976) – Keiko
• 杳子 (Yuko) (1977) – Sayako
• Lost Love (1978) – Asuka Yamazaki
• 四季の追想 (Reminiscences of the Four Seasons) (1979, short)
• Fashion (1980, TV), "Kansai in New York" – Self
• Fruits of Passion (1981) – Sakuya
• Rikyū (1989) – Chacha
• 石の花 (Stone Flowers) (1989, documentary short) – Self
• T-CITY (1993, video short) – Woman
• Pistol Opera (2001) – Sayoko Uekyo
• Soundtrack (2002) – Red monster
• Matouqin Nocturne (2007) – Zarome
• Kōri no hanabi Sayoko Yamaguchi (Ice Fireworks Sayoko Yamaguchi) (2015, posthumous documentary) – Self