Isothermal vapor-liquid equilibrium (VLE) data are measured for the ternary systems of methyl tertbutyl ether (MTBE) + methanol + methylcyclohexane (MCH) and MTBE + methanol + n-heptane and constituent four binary systems, MTBE + MCH, MTBE + n-heptane, methanol + MCH, and methanol + n-heptane, at 313.15 K. The experimental binary VLE data were correlated with common g(E) model equations. The correlated Wilson and NRTL parameters of the constituent binary systems were used to calculate the phase behavior of the ternary mixtures. The calculated ternary VLE data using Wilson and NRTL parameters and the predicted data using modified UNIFAC (Dortmund) model were compared with experimental ternary data.