Surname Agust (Agust 
, Ágúst 
, สิงหาคม 
) , in the world, is quite a rare family name. The surname Agust is habitual in Iceland, where it is quite a common surname, Tanzania, where it is a rare surname, and Indonesia. Measured by absolute frequency, it most frequently occurs in Indonesia, Tanzania, and Guatemala. More prevalently, Agust is the forename as well as the last name.