Last name Ong Siu (Ong Siu 
) , in all the world, is a very rare surname. The family name Ong Siu is habitual in Philippines, where it is an extremely rare surname, and China. Also, Ong Siu is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Ong Siu | China, Philippines |