Family name Casek (Casek 
) , in the entire world, is a rare surname. The last name Casek is habitual in Czechia, where it is quite a rare surname, Austria, where it is a rare surname, and Philippines, where it is an extremely rare surname. Measured by absolute frequency, it is the most numerous in Czechia, Austria, and the United States. Much less frequently, Casek is the forename as well as the last name.