Surname قسي (قسي 
, Cassus 
) , worldwide, is a rare last name. The surname قسي is characteristic of Jordan, where it is a rare surname, France, and Saudi Arabia. Measured by absolute frequency, the name is most common in France, Saudi Arabia, and Algeria. Much less frequently, قسي is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| قسي | Morocco, Iraq, Jordan, Saudi Arabia, Algeria |
| Cassus | France, Italy, Brazil, Chile, United States |