Family name สมาธิ (Samsad 
, สมาธิ , Samathi 
) , all over the world, is quite a common last name. The cognomen สมาธิ is habitual in Qatar, where it is quite a rare surname, Saudi Arabia, and Thailand. Measured by absolute frequency, the name is most common in India, Thailand, and Saudi Arabia. More frequently, สมาธิ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Samsad | Saudi Arabia, Nepal, Bangladesh, Thailand, India |
| สมาธิ | Thailand |
| Samathi | United States, Malaysia, Thailand, France, India |
| Meddings | Canada, United Kingdom, United States, Germany, Australia |
Medhavit, Medhawat, Samadah, Samadhanay, Samadtiram, Samiddhi, Samnia, Semintendi, and Smaati