Family name Gaku (Gaku 
, ガク , Гаку 
) , worldwide, is a common last name. The family name Gaku is habitual in Japan, where it is quite a common surname, Gambia, where it is quite a rare surname, and Kenya, where it is a rare surname. In absolute terms, the name is most common in Japan, Kenya, and Nigeria. Much less frequently, Gaku is the forename as well as the last name.