The extraction of Ga3+ and Al3+ with the liquid cation-exchangers di-n-butyldithiophosphoric acid (DBTPA) and di-(2-ethylhexyl)dithiophosphoric acid (DETPA) in kerosene, in the presence and absence of alcohols and tri-n-butyl phosphate (TBP) has been studied. Both Ga3+ and Al3+ can be extracted in the form of a neutral complex, MA3, but the distribution coefficient of Ga3+ is the higher by about two orders of magnitude, which can be the basis of the solvent extraction separation of gallium and aluminium. The differences can be explained by the interaction between the sulphur donor atoms of the extractants and the d10 electronic shell of Ga3+ as well as by the lower steric hindrance of ligands co-ordinated to Ga3+.