Surname Raiou (Раю 
, Райу , Raiou 
) , across the world, is a rare family name. The cognomen Raiou is habitual in Moldova, where it is quite a rare surname, Bulgaria, and Greece, where it is a rare surname. In absolute terms, this name is the most popular in Eastern Europe, particularly Russia, Bulgaria, and Moldova. Likewise, Raiou is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Раю | Bulgaria, Ukraine, Moldova, Belarus, Russia |
| Райу, Раиу | Russia |
| Raiou | Brazil, Greece |