Family name Mlej (Mlej 
) , all over the world, is a very rare cognomen. The family name Mlej is habitual in Czechia, where it is a rare surname, and China, where it is an extremely rare surname.
| VARIANT | COUNTRY |
|---|---|
| Mlej | China, Czechia |
| ivan mlej SK (b. 1922) |
|
|
| viktor mlej |
|