Family name Сейил (Сейил 
, Seiil 
, Seyil 
) , across the world, is a rare cognomen. The last name Сейил is characteristic of Kyrgyzstan, where it is quite a rare surname, Kazakhstan, where it is a very rare surname, and the United States, where it is an extremely rare surname. Also, Сейил is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Сейил | Kyrgyzstan, Kazakhstan, Russia |
| Seiil | United States, Russia, United Arab Emirates, Kazakhstan |
| Seyil | India, Canada, United States |