Cognomen นินจา (Ninj 
, นินจา 
, Ninkeeree ) , all over the world, is a rare surname. The last name นินจา is habitual in Mongolia, where it is quite a rare surname, Myanmar, where it is a very rare surname, and Thailand. In absolute terms, this name is the most popular in Mongolia, India, and Myanmar. Likewise, นินจา is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Ninj | Myanmar, United States, New Zealand, Mongolia, India |
| Ninkeeree, Ninjant, นินจา | Thailand |
Ninak, Ninan, Ninareeman, Ninasran, Ninasree, Ninasreen, Ninasri, Ninasriya, Ninasroon, Ninbowron, Nincha, Nincham, Ninja, Ninjaa, Ninjamrern, Ninjan, Ninjang, Ninjar, Ninjarad, Ninjaras, Ninjarus, Ninjinda, Ninjit, Ninjo, Ninjong, Ninjumras, Ninjumrus, Ninjun, Ninjutturus, Ninkew, Ninlamas, Ninlaphut, Ninlaves, Ninlom, Ninmas, Ninmon, Ninmot, Ninmote, Ninon, Ninooch, Ninpak, Ninpaksa, Ninpan, Ninpankan, Ninphailot, Ninphala, Ninphan, Ninphap, Ninphay, Ninphom, Ninphun, Ninphung, Ninprakhon, Ninrak, Ninraksa, Ninramoj, Ninrut, Ninsa, Ninsamai, Ninunr, Ninursana, Ninusree, Ninut, Ninvas, Ninwana, Ninworn, Ninya, and 忍者