Cognomen Ninj (Ninj 
) , worldwide, is a rare surname. The family name Ninj is habitual in Mongolia, where it is quite a rare surname, Myanmar, where it is a very rare surname, and India, where it is an extremely rare surname. Also, Ninj is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Ninj | Mongolia, Myanmar, India, New Zealand, United States |