Consistent vapor-liquid equilibrium data at 101.3 kPa have been determined for the ternary system diisopropyl ether (1) + 2-propyl alcohol (2) + n-butyl propionate. (3) and two constituent binary systems: diisopropyl ether (1) + n-butyl propionate (3) and 2-propyl alcohol (2) + n-butyl propionate (3). The diisopropyl ether (1) + n-butyl propionate (3) system does not present deviation from ideal behavior, and the 2-propyl alcohol (2) + n-butyl propionate (3) system shows light positive deviation from Raoult's law. The activity coefficients of the solutions were correlated with their compositions by the Wilson, NRTL, and UNIQUAC models. Wisniak-Tamir equations were used to correlate the boiling points of the solutions with its composition. The binary VLE data measured in the present study passed the thermodynamic consistency test of Fredeslund et al. The ternary system is very well predicted from binary interaction parameters and passed both the Wisniak L-W and McDermott-Ellis consistency tests. The change of phase equilibria behavior due to solvent is insignificant; therefore, this solvent seems not to be an effective agent for the separation of the azeotropic mixture by extractive distillation.