Family name Русай (Rusai 
, Rusay 
, Русай 
) , worldwide, is a rare cognomen. The last name Русай is characteristic of Hungary, where it is a rare surname, Estonia, and Czechia. In absolute terms, this name is the most popular in Hungary, the United States, and Indonesia. More prevalently, Русай is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Rusai | Malaysia, China, India, Indonesia, Hungary |
| Rusay | Philippines, Brazil, India, United States, Venezuela |
| Русай | Russia, Kazakhstan |
| Rusaj | United Kingdom, United States, Czechia, India |