Family name Justo Gerardo (Justo Gerardo 
) , worldwide, is an extremely rare cognomen. The cognomen Justo Gerardo is characteristic of Latin America and the Caribbean, particularly Chile, where it is an extremely rare surname. Much more prevalently, Justo Gerardo is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Justo Gerardo | Costa Rica, Peru, Ecuador, Spain, Chile |