Scandium is a metal of value with increasing demand but limited supply. During the valorization of bauxite residue, scandium becomes concentrated in an NH4F strip liquor, from which it can be recovered as (NH4)3ScF6 by antisolvent crystallization. This study investigates the use of different antisolvents and their concentrations on the morphology and crystal size of the (NH4)3ScF6 crystals produced. The antisolvents include alcohols, ketones, and a sulfoxide. These were added all at once, either pure or diluted, to the aqueous solution to attain final concentration of 2, 4, or 8 mol/L total solution in separate experiments. Changes in the functional group and concentration of the antisolvents were observed to induce morphological and crystal size modifications of (NH4)3ScF6. The differences are likely due to the specific interactions of the antisolvent molecules with the atoms at the different faces of the crystals.