Family name Sysoy (Сысой 
, Sysoy , Сысои ) , around the world, is quite a rare last name. The family name Sysoy is habitual in Eastern Europe, particularly Belarus, where it is quite a common surname, Russia, where it is a rare surname, and Ukraine, where it is an extremely rare surname. Much less frequently, Sysoy is the forename as well as the last name.