Kosugi (written: 小杉 lit. "small Japanese cedar" or コスギ in katakana) is a Japanese surname. Notable people with the surname include:
Isamu Kosugi (小杉 勇) (1904–1983), Japanese actor and film directorJūrōta Kosugi (小杉 十郎太) (born 1957), Japanese voice actorKane Kosugi (ケイン・コスギ) (born 1974), American karateka and actorSho Kosugi (ショー・コスギ) (born 1948), Japanese karateka and actorShunji Kosugi (小杉 俊二) (born 1960), Japanese professional wrestlerTakashi Kosugi (小杉 隆) (born 1935), Japanese politicianTakehisa Kosugi (小杉 武久) (born 1938), Japanese classical composerKosugi Tengai (小杉 天外) (1865–1952), pen-name of Kosugi Tamezō, Japanese writerToshiyuki Kosugi (小杉 敏之) (born 1968), Japanese footballer