Family name Vatslav (Вацлав 
, Вацлаў , Ватцлав ) , worldwide, is a very rare cognomen. The family name Vatslav is characteristic of Bulgaria, where it is a rare surname, Ukraine, and Kazakhstan, where it is a very rare surname. Measured by absolute frequency, it most frequently occurs in Eastern Europe, particularly Ukraine, Bulgaria, and Russia. Predominantly, Vatslav is the forename as well as the last name.