The extraction of gallium(III) complex ion from aqueous oxalic acid solutions with tri- n-octylamine in xylene has been investigated and the effects of pH, of a mole ratio of oxalate to gallium(III) and of amine and gallium(III) concentrations on the gallium(III) extraction have been measured. Also, gallium(III) species in aqueous oxalic acid solutions have been examined using the amine extraction method. A mechanism for the extraction of gallium(III) complex ion was discussed on the basis of the results obtained.