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