Last name โดย (Doi 
, By , โดย 
) , throughout the world, is a common cognomen. The surname โดย is habitual in Myanmar, where it is quite a common surname, Norway, where it is quite a rare surname, and Taiwan. In absolute terms, it is the most numerous in Myanmar, Indonesia, and India. Likewise, โดย is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Doi, By | Myanmar, United States, India, Indonesia, China |
| โดย | Thailand |
| Byth | Australia, Canada, United States, United Kingdom, Indonesia |