Isogai (written: 磯貝, 磯谷 or 礒貝) is a Japanese surname. Notable people with the surname include:

, Japanese judoka , Japanese footballer , Japanese general , Japanese singer and musician , Japanese sport wrestler

Fictional characters , a character in the manga series Assassination Classroom , a character in the anime series Little Battlers Experience WARS

See also 8251 Isogai, a Mars-crossing asteroid