Surname Kostiou (Kostiou 
, Костю 
) , worldwide, is a rare last name. The cognomen Kostiou is habitual in Ukraine, where it is a rare surname, Greece, and Russia, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| Kostiou | Greece, United States |
| Костю | Ukraine, Russia |
| jeremi kostiou (b. 1991) |
|