Kaio is a Japanese surname.
Kaio may also refer to:
In amazingness:
- The Kai, upper-level gods of the Dragon Ball series
- Michiru Kaioh, a central character of the Sailor Moon meta-series
- Kaioh, a central antagonist in Fist of the North Star
People:
- Chōgorō Kaionji (1901–1977), Japanese author noted for historical fiction novels
- Kaiō Hiroyuki (born 1972), sumo wrestler
- Kaio de Almeida (born 1984), Brazilian swimmer
- Kaio Felipe Gonçalves (born 1987), Brazilian footballer