Usui (written: 碓井, 碓氷, 臼井, 笛吹 or 卯水) is a Japanese surname. Notable people with the surname include:
Hana Usui (born 1974), Japanese artistHideo Usui (born 1939), Japanese politicianHiroyuki Usui (born 1953), former Japanese football player and managerHitoshi Usui (born 1988), Japanese football playerJunichi Usui (born 1957), retired Japanese long jumperKaoru Usui (born 1916), photographerKempei Usui (born 1987), Japanese footballerKohei Usui (born 1979), Japanese football playerMasahiro Usui (born 1991), Japanese actorMasako Usui (born 1968), Japanese newscasterMikao Usui (1865–1926), religious teacher, founder of ReikiMikoto UsuiRie Usui (born 1989), Japanese women's footballerUsui Sadamitsu, warriorYoshimi Usui (1905–1987), Japanese author and criticYoshito Usui (1958–2009), Japanese manga artistAs given name:
Usui Kojima (1873–1948), Japanese authorFictional characters:
Kazuyoshi Usui or Switch, a character in anime and manga series Sket DanceHorokeu Usui or Horohoro, a character in anime and manga series Shaman KingUonuma Usui, a character in anime and manga series Rurouni Kenshin