Cognomen Janseng (Janseng 
) , worldwide, is a rare last name. The cognomen Janseng is characteristic of Thailand, where it is a rare surname, and Honduras, where it is a very rare surname. Likewise, Janseng is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Janseng | United States, Honduras, India, Thailand |