Liquid-liquid equilibrium data for the systems sulfolane + octane + benzene, sulfolane + octane + toluene, and sulfolane + octane + p-xylene were determined at 343.35 K, 372.35 K, and 402.35 K; Tie line data were satisfactorily correlated by the Othmer and Tobias method. The experimental data were compared with the values calculated by the UNIQUAC and NRTL models. Good qualitative agreement was obtained with these models. However, the calculated values based on the NRTL model were found to be better than those based on the UNIQUAC model.