Inui (乾, lit. "northwest") is a Japanese surname. Notable people with the surname include:
- Daichi Inui (born 1989), Japanese association football player (J1 League)
- Emi Inui (born 1983), Japanese Olympic softball player
- Kurumi Inui (born 1963), Japanese novelist and mystery writer
- Masahiro Inui (born 1988), Japanese baseball player
- Sekihiko Inui (fl. 2005–present), Japanese manga artist
- Takashi Inui (born 1988), Japanese association football player in Europe
- Takaya Inui (born 1990), Japanese association football player (J2 League)
- Tatsuro Inui (born 1990), Japanese association football player in Southeast Asia
- Yukiko Inui (born 1990), Japanese synchronized swimmer