Family name Илко (Ilko 
, Илко 
) , in all the world, is quite a rare cognomen. The cognomen Илко is characteristic of Slovakia, where it is quite a rare surname, Bulgaria, and North Macedonia. Not in comparison with a country's population, it is commonest in Slovakia, the United States, and Czechia. Likewise, Илко is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Ilko | Germany, Bulgaria, United States, Slovakia, Czechia |
| Илко | Bulgaria, Russia, Kazakhstan |
Elias, Eliasz, Elie, Elies, Eliáš, Ellie, Elías, Ilia, Ilian, Ilias, Ilie, Ilija, Ilijan, Iliyan, Ilià, Iliá, Ilián, Ilja, Illa, Illes, Illia, Illja, Illya, Illés, Ilya, Élie, Ελίας, Ηλίας, Илеш, Илиан, Илиас, Илие, Илия, Илија, Иллеш, Илля, Илчо, Ильюша, Илья, Илюха, Илюша, Иля, Эли, Элиас, Элиаш, Ілля, Ілья, Іліас, איליה, אילש, אליאס, إليا, إلياس, إيلي, إيليا, ایلیا, خوسيه, ილია, イリア, イリアス, イリエ, イリヤ, エリ, エリアス, エリー, 埃利, 埃利亚斯, and 艾利