Equilibrium tie line data have been determined at (323.15, 348.15, and 373.15) K for the ternary liquid-liquid equilibria (LLE) of three alkane + hexylbenzene + sulfolane systems, where the alkanes studied are decane, dodecane, and tetradecane. The relative mutual solubility of hexylbenzene is higher in decane + sulfolane than in dodecane + sulfolane or tetradecane + sulfolane mixtures. The tie line data were correlated with the UNIQUAC and NRTL models. The calculated values based on the UNIQUAC model were found to be better than those based on the NRTL model. The values of selectivity and distribution coefficients were calculated from the equilibrium data.