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 | Myanmar, United States, Tanzania, Cameroon, Democratic Republic of the Congo |
| Jastin | United States, Tanzania, India, Myanmar, Democratic Republic of the Congo |
| Castin | South Africa, United States, India, Canada, Democratic Republic of the Congo |
| จัสติน | Thailand |