Surname Kljain (Kljain 
, Кляин 
) , around the globe, is a rare last name. The cognomen Kljain is habitual in Kazakhstan, where it is quite a rare surname, Estonia, where it is a rare surname, and Russia, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| Kljain | Germany, Estonia |
| Кляин | Kyrgyzstan, Kazakhstan, Russia, Ukraine |