Surname มโนธรรม (Manotham 
, มโนธรรม , Manonom ) , in all the world, is quite a rare family name. The last name มโนธรรม is characteristic of Laos, where it is quite a common surname, Thailand, where it is quite a rare surname, and Canada, where it is a very rare surname. In absolute terms, it is the most numerous in Laos, Thailand, and the United States. Likewise, มโนธรรม is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Manotham | United States, Laos, Canada, Thailand |
| มโนธรรม, Manonom | Thailand |
| Manootham | Malaysia, Thailand |
Manohtam, Manoontham, Manothom, Maothap, Moadpradisth, and Monotham