Surname จัสติน (Justin 
, Jastin 
, Castin 
) , in all the world, is a common last name. The surname จัสติน is characteristic of Saint Lucia, where it is a common surname, Brunei, where it is quite a common surname, and Slovenia (explore the name in all countries). Not in comparison with a country's population, the name is most common in Sub-Saharan Africa, particularly Nigeria, Cameroon, and Tanzania. More prevalently, จัสติน is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Justin | Democratic Republic of the Congo, Cameroon, Tanzania, United States, Myanmar |
| Jastin | Democratic Republic of the Congo, Tanzania, United States, India, Myanmar |
| Castin | Democratic Republic of the Congo, United States, India, South Africa, Canada |
| จัสติน | Thailand |