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 | Finland, Indonesia, United States, Italy, Papua New Guinea |
| Kaija | Finland, Uganda, Sweden, United States, India |
| Caia | Romania, Argentina, United States, Italy, India |
| Кайя | Kazakhstan, Russia, Ukraine |