Cognomen Simplicius (Simplicius 
) , in the world, is a very rare surname. The cognomen Simplicius is habitual in Sub-Saharan Africa, particularly Nigeria, where it is a very rare surname. Likewise, Simplicius is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Simplicius | Italy, India, Nigeria, South Africa |
Simplici, Simplicio, Simplisius, and Simplício
| jernej simplicius SI |
|