Cognomen Felsi (Felsi 
) , across the world, is a very rare family name. The surname Felsi is habitual in Italy, where it is a very rare surname, Venezuela, and Peru, where it is an extremely rare surname. Measured by absolute frequency, it most frequently occurs in India, Italy, and Nigeria. More frequently, Felsi is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Felsi | Colombia, Venezuela, Italy, India, Nigeria |