Family name Tret'Yakov (Третьяков 
, Tret'Yakov 
) , around the globe, is a common cognomen. The family name Tret'Yakov is characteristic of Belarus, where it is quite a common surname, Russia, and Kazakhstan. Not in comparison with a country's population, the name is most common in Russia, Ukraine, and Kazakhstan.
| VARIANT | COUNTRY |
|---|---|
| Третьяков | Kazakhstan, Russia, Kyrgyzstan, Belarus, Ukraine |
| Tret'Yakov | Russia, Czechia, Belarus, Bulgaria, Ukraine |