Family name Sinnamuthu (Sinnamuthu 
) , globally, is a rare last name. The last name Sinnamuthu is characteristic of Malaysia, where it is a rare surname, the United Kingdom, where it is an extremely rare surname, and the United States. Much less frequently, Sinnamuthu is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Sinnamuthu | Malaysia, United Kingdom, India, United States |