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 | Ethiopia, Turkey, Malaysia, India, United Arab Emirates |
| Sayin | Germany, Turkey, Malaysia, Indonesia, India |
| Saiin | Japan, Thailand, Malaysia, Indonesia, India |
| Сайин | Kazakhstan, Russia, Uzbekistan, Ukraine |