Family name سيس (Sis 
, Cees 
, سيس 
) , throughout the world, is a common last name. The cognomen سيس is characteristic of Guatemala, where it is quite a common surname, Myanmar, and Norway, where it is quite a rare surname. Not in comparison with a country's population, the name is most common in Guatemala, Myanmar, and Indonesia. Also, سيس is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Sis | Netherlands, Indonesia, Guatemala, Myanmar, India |
| Cees | Netherlands, Malaysia, Indonesia, United States, India |
| سيس | Morocco, Egypt, Sudan, Iraq, Algeria |
| Syse | Spain, United Kingdom, United States, Poland, Norway |