Cognomen Karlain (Karlain 
) , worldwide, is an extremely rare last name. The family name Karlain is characteristic of Latin America and the Caribbean, particularly Venezuela, where it is an extremely rare surname, and Mexico. Much more frequently, Karlain is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Karlain | Philippines, Mexico, United States, India, Democratic Republic of the Congo |