Last name ยัย (Yai 
, Yuai 
, ยัย 
) , in the world, is a common surname. The family name ยัย is characteristic of Myanmar, where it is quite a rare surname, Benin, and Malaysia. Measured by absolute frequency, it is the most numerous in Myanmar, Japan, and India. Also, ยัย is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Yai | Myanmar, Ethiopia, Japan, Malaysia, India |
| Yuai | Myanmar, China, Japan, Malaysia, India |
| ยัย | Thailand |