Family name Sook-Ja (숙자 
, Sook-Ja 
) , across the world, is an extremely rare last name. The cognomen Sook-Ja is habitual in Northern America, particularly the United States, where it is an extremely rare surname. Much more frequently, Sook-Ja is the forename as well as the last name. Parts of the name also exists independently as a first name Sook, and a first name Ja.