Surname Gillias (Gillias 
) , in the entire world, is a very rare cognomen. The cognomen Gillias is characteristic of Belgium, where it is a rare surname, Tanzania, where it is a very rare surname, and the United Kingdom. Much less frequently, Gillias is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Gillias | Belgium, Tanzania, United States, United Kingdom, South Africa |