All over the world, Casillo (Casillo 
) is a very rare mostly masculine, but seldom girly forename. The given name Casillo is characteristic of Southern Europe, particularly Italy, where it is a rare mostly male, but seldom feminine name. Much more frequently, Casillo is the last name as well as the forename.
| VARIANT | COUNTRY |
|---|---|
| Casillo | Eswatini, Philippines, Bolivia, Italy, United States |