Consistent vapor-liquid equilibrium data for the binary and ternary systems ethanol + 2-methyl-2-propanol (TBA) and 2-methylpentane + ethanol + TEA are reported at 101.3 kPa. In the binary system, the results indicate a negative deviation from ideality and no azeotrope is present. The ternary system shows negative and positive deviations from ideality, does not present azeotrope, and is well predicted from binary data. The activity coefficients and boiling points of the solutions were correlated with its composition by Wilson, UNIQUAC and NRTL equations.