Liquid-liquid equilibrium data were measured at 293.15 K for five different pseudo-ternary systems. Two components are kept the same (octane and toluene), but the other one, a pseudo-component, is made up of a mixture of sulfolane with a small amount of a 1-alkanol (methanol + ethanol, + 1-propanol, + 1-butanol, or + 1-pentanol). The nonrandom two liquid (NRTL) equation was used to correlate the experimental data and to predict the phase composition of the systems studied. The agreement between the correlated and the experimental results was good.