Liquid-liquid equilibrium (LLE) results for ternary mixtures of {methanol (1) + methylbenzene (2) + decane (3)} at different temperatures from (298.15 to 313.15) K are reported. The compositions of the liquid phases at equilibrium were determined by gas-liquid chromatography. The data were correlated with the NRTL and UNIQUAC equations. Also, the selectivity and distribution coefficient of methanol for the extraction of methylbenzene from decane at different temperatures are compared. The phase diagrams for the ternary mixtures are presented, and the correlated tie line results are compared with the experimental data. The comparison indicates the applicability of the NRTL and UNIQUAC activity coefficient models for LLE calculations on the studied mixtures.