Cognomen Vjačeslav (Вячеслав 
, Вйачеслав , Vjačeslav 
) , all around the world, is a common family name. The surname Vjačeslav is characteristic of Kyrgyzstan, where it is quite a common surname, Moldova, and Armenia. Measured by absolute frequency, it is commonest in Russia, Kyrgyzstan, and Uzbekistan. Much more frequently, Vjačeslav is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Вячеслав | Kazakhstan, Russia, Kyrgyzstan, Belarus, Ukraine |
| Вйачеслав | Russia |
| Vjačeslav | Croatia, Czechia |
Vaclau, Vaclaw, Vencel, Venceslao, Venceslav, Ventseslav, Venčeslav, Viachaslau, Viacheslav, Viatcheslav, Vjaceslav, Vjacseszlav, Vjatjeslav, Vjatsjeslav, Vjatšeslav, Vyachaslau, Vyachaslaw, Vyacheslav, Václav, Věnceslav, Wacław, Wenzel, Wenzeslaw, Więcesław, Wjatscheslaw, В'Ячеслав, Вацлав, Вацлаў, Венцел, Венцель, Венцеслав, Венчеслав, Вячаслав, Вячаслаў, and Слава