Family name Сайин (Sajin 
, Sayin 
, Saiin 
) , around the world, is a common cognomen. The family name Сайин is habitual in Turkey, where it is quite a common surname, Moldova, and Montenegro, where it is quite a rare surname. In absolute terms, this name is the most popular in Turkey, Ethiopia, and India. Likewise, Сайин is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Sajin | Turkey, Ethiopia, United Arab Emirates, Malaysia, India |
| Sayin | Turkey, Germany, Indonesia, Malaysia, India |
| Saiin | Japan, Indonesia, Malaysia, Thailand, India |
| Сайин | Uzbekistan, Russia, Ukraine, Kazakhstan |