Liquid-liquid equilibrium data are presented for the ternary systems: sulfolane + p-xylene + cyclohexane, sulfolane + p-xylene + n-hexane and sulfolane + toluene + n-hexane at 308.15 and 323.15 K. Tie-line data were correlated by Hand and Othmer-Tobias methods with correlation coefficients near unity. Parameters for NRTL and UNIQUAC activity coefficient models were estimated. The NRTL model fits slightly better the liquid-liquid equilibrium data of the systems studied. The root mean square deviations (RMSDs) obtained comparing calculated and experimental two-phase compositions are <1.61% for NRTL model and <2.1% for UNIQUAC model.