Cognomen Eustathios (Eustathios 
, Ευστάθιος ) , in all the world, is a very rare family name. The family name Eustathios is characteristic of Northern America, particularly the United States, where it is an extremely rare surname. More frequently, Eustathios is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Eustathios | Germany, United Kingdom, Italy, United States, Greece |
| Ευστάθιος | Greece |
Efstathios, Eustac, Eustacchio, Eustace, Eustach, Eustache, Eustachio, Eustachy, Eustacio, Eustacius, Eustacjusz, Eustahije, Eustaqui, Eustaquio, Eustasio, Eustasius, Eustazio, Eustazy, Eustațiu, Eustácio, Eustáquio, Evstafy, Evstahij, Ostap, Stathis, Στάθης, Астафий, Евстатий, Евстафий, Евстахий, Остап, Остафий, Стафей, Эсташ, Юстас, and Євстафій
Edel, Bacas, Zikos, Marcos, Spanos, Stratis, Sainidis, Staikidis, Kokolakis, Ioannides, Aposporidis, Eustathiou, and Papadopoulos