Yoshihide Kozai (1 April 1928 – 5 February 2018) was a Japanese astronomer specialising in celestial mechanics.

He is best known for discovering, simultaneously with Michael Lidov, the Kozai mechanism, for which he received the Imperial Prize of the Japan Academy in 1979.

He became the director of the Domestic Satellite Computing Facility of the Tokyo Astronomical Observatory in 1965.

[2] He was awarded the Imperial Prize of the Japan Academy in 1979 for discovering the Kozai mechanism.

[1] In 1988, Kozai became the first Japanese person to become the president of the International Astronomical Union.