Family name Кайя (Kaia 
, Kaija 
, Caia 
) , globally, is quite a common last name. The last name Кайя is characteristic of Finland, where it is quite a rare surname, Romania, and Uganda. Not in comparison with a country's population, it is the most numerous in Uganda, Romania, and Italy. Likewise, Кайя is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Kaia | United States, Papua New Guinea, Finland, Indonesia, Italy |
| Kaija | India, Uganda, United States, Sweden, Finland |
| Caia | Argentina, India, Romania, United States, Italy |
| Кайя | Russia, Kazakhstan, Ukraine |