Surname Rioo (Rioo 
) , around the globe, is quite a rare cognomen. The last name Rioo is characteristic of Japan, where it is quite a rare surname, Myanmar, where it is a very rare surname, and Indonesia. Measured by absolute frequency, it is commonest in Japan, Indonesia, and Egypt. Very seldom, Rioo is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Rioo | Myanmar, Egypt, Indonesia, Japan, Saudi Arabia |