Family name Gretia (Gretia 
) , worldwide, is an extremely rare surname. The cognomen Gretia is habitual in Latin America and the Caribbean, particularly Nicaragua, where it is a very rare surname, and Venezuela, where it is an extremely rare surname. Much more frequently, Gretia is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Gretia | Indonesia, South Africa, United States, France, Brazil |