Kozai may refer to:
- Kozai-Lidov mechanism, a dynamical phenomenon in celestial mechanics
- 3040 Kozai, an asteroid
Persons with the surname Kozai
edit- Yoshihide Kozai (1928–2018), Japanese astronomer
- Kazuteru Kozai (born 1986), Japanese badminton player
- Kaori Kozai (born 1963), Japanese singer
- Takeshi Kozai (1974–2006), Japanese judoka