Surname Castillanos (Castillanos 
) , around the world, is a very rare last name. The family name Castillanos is habitual in Canada, where it is a very rare surname, Honduras, and Mexico, where it is an extremely rare surname. Measured by absolute frequency, it is the most numerous in the United States, Mexico, and Canada.
| VARIANT | COUNTRY |
|---|---|
| Castillanos | Mexico, Venezuela, United States, Canada, Philippines |