A systematic study of solvent extraction behaviour of trivalent scandium, yttrium and lanthanum with tributyl phosphine oxide from salicylate media is carried out, and a scheme for separation for scandium-yttrium and scandium-lanthanum is discussed. Scandium (III) is quantitatively extracted from 1.25 x 10(-2)-1.88 x 10(-2) M sodium salicylate at pH 3.8-4.2 with 2.3 x 10(-3) M TBPO dissolved in toluene, Yttrium is quantitatively extracted at pH 4.5-6.0 from 1.25 x 10(-2)-5 x 10(-2) M sodium salicylate with 2.3 x 10-3 M TBPO dissolved in toluene while lanthanum is extracted at pH 4.8-8.0 from 2.5 x 10(-2)-6.25 x 10(-2) M sodium salicylate with 4.58 x 10(-3) M TBPO dissolved in toluene. A possible mechanism for the extraction is proposed. The extracted metal ions were separated by selective stripping and estimated spectrophotometrically following a complexation with PAR and Thoron I. The proposed method facilitates the separation and determination of scandium, yttrium and lanthanum from binary and synthetic mixtures.