Cognomen Sevastyan (Севастьян 
, Севастян , Sevastyan 
) , in all the world, is a rare last name. The family name Sevastyan is characteristic of Ukraine, where it is a rare surname, Belarus, where it is a very rare surname, and Kyrgyzstan. Not in comparison with a country's population, it most frequently occurs in Eastern Europe, particularly Ukraine, Russia, and Belarus. More prevalently, Sevastyan is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Севастьян | Ukraine, Kazakhstan, Belarus, Russia, Kyrgyzstan |
| Севастян | Kazakhstan, Russia, Ukraine |
| Sevastyan | Russia, United States, India |