Isothermal vapor-liquid equilibrium (VLE) data at 333.15 K are reported for the binary systems of di-n-butyl ether (DBE) + ethanol, ethanol + benzene, DBE + benzene, and the ternary system of DBE + ethanol + benzene by using headspace gas chromatography. The experimental binary VLE data were correlated with common G (E) model equations. The ternary VLE data were correlated also with Wilson, NRTL, and UNIQUAC models. Additionally the excess molar volumes (V (E)) and deviations in molar refractivity (Delta R) at 298.15 K for the constituent binary and ternary systems of DBE + ethanol + benzene were determined from measured densities and refractive indices. The experimental V (E) and Delta R were correlated with Redlich-Kister or Cibulka equation for the binary and ternary systems, respectively. The ternary V (E) and Delta R were also compared with the estimated values from the binary contribution models of of Tsao-Smith, Kohler, Rastogi, and Radojkovic.