Worldwide, Николаев (Николаев 
, Nikolaev 
, Nikolajew 
, along with others...) is a rare male first name. The first name Николаев is habitual in Eastern Europe, particularly Bulgaria, where it is quite a rare masculine name, Romania, where it is a rare boy's name, and Russia, where it is a very rare male name. In absolute terms, this name is the most popular in Bulgaria, Russia, and China. Much more frequently, Николаев is the last name as well as the forename.
| VARIANT | COUNTRY |
|---|---|
| Николаев | Azerbaijan, Kazakhstan, Russia, Belarus, Ukraine |
| Nikolaev | Uzbekistan, Russia, Estonia, Bulgaria, United States |
| Nikolajew | Germany, Estonia, Finland, United States, Poland |
| Nikolayev | Germany, Russia, Spain, Estonia, United States |
| Nikolajev | Czechia, Estonia, Serbia, United States, Lithuania |
Klaas, Mikalai, Mikalaj, Mikalay, Mikałaj, Miklavž, Miklos, Miklós, Mikola, Mikołaj, Mikuláš, Mikławš, Mykola, Mykoła, Niccolò, Nicholas, Nickel, Nicolaas, Nicolae, Nicolaes, Nicolas, Nicolau, Nicolay, Nicolino, Nicolo, Nicolás, Nicolò, Nicos, Nicu, Niels, Nikola, Nikolai, Nikolai, Nikolaj, Nikolaj, Nikolajevs, Nikolajs, Nikolajus, Nikolao, Nikolaos, Nikolas, Nikolass, Nikolaus, Nikolay, Nikolayew, Nikolaz, Nikolaï, Nikolaïev, Nikos, Nikołaj, Nikulás,
Николаев is also a prevalent name for the fictitious and mythical characters: Nick Wilde , the Zootopia character; Nick Fury , the fictional character from the Marvel Cinematic Universe, Avengers: Infinity War; Michael Darling , the fictional character from Peter Pan; Nearly Headless Nick , character in Harry Potter and Nicholas Brody , the fictional character on the American television/drama thriller Homeland, and in many other works.