All around the world, โออิน (Oin 
, Oain 
, โออิน ) is a rare unisex first name. The forename โออิน is characteristic of Romania, where it is a rare boy's name, Indonesia, where it is a very rare gender-neutral name, and Nigeria, where it is an extremely rare epicene name. In absolute terms, it is the most numerous in Indonesia, Romania, and India. More prevalently, โออิน is the last name as well as the forename.
| VARIANT | COUNTRY |
|---|---|
| Oin | Indonesia, Taiwan, Romania, Malaysia, Thailand |
| Oain | India, United States, Brazil |
| โออิน | Thailand |