Surname Илай (Ilai 
, Ilay 
, Ilaj 
) , around the world, is quite a rare cognomen. The last name Илай is characteristic of Papua New Guinea, where it is quite a rare surname, Israel, where it is a rare surname, and United Arab Emirates. In absolute terms, the name is most common in India, Papua New Guinea, and Philippines. More prevalently, Илай is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Ilai | Fiji, Papua New Guinea, India, Myanmar, Israel |
| Ilay | Philippines, Madagascar, India, Myanmar, Israel |
| Ilaj | Morocco, Kuwait, United States, India, Pakistan |
| Илай | Kyrgyzstan, Russia |