Cognomen Vailo (Vailo 
, Вайло 
) , around the world, is a rare last name. The surname Vailo is characteristic of Ukraine, where it is quite a rare surname, Kazakhstan, where it is a rare surname, and Portugal, where it is a very rare surname. Measured by absolute frequency, this name is the most popular in Ukraine, Russia, and Kazakhstan. Very seldom, Vailo is the forename as well as the last name.