Liquid-liquid equilibrium data for methyl tert-butyl ether (MTBE) + ethanol + water and MTBE + 1-hexanol + water have been experimentally measured over the temperature range of 288.15 to 308.15 K. The equilibrium data of this work, in addition to the available MTBE-containing LLE data in the technical literature, are analyzed using UNIQUAC, NRTL, UNIFAC-LL, and UNIFAC-DMD models as programmed by the Aspen Plus simulator. On the basis of analyses of the experimental data of this work, UNIFAC-LLE and UNIFAC-DMD showed the best predictive performance for the mole fraction of the target species (MTBE) in both the organic and aqueous phases.