Excess molar volumes (V-E) and deviations in molar refraction (Delta R) and isentropic compressibility (Delta kappa(s)) upon mixing were determined for homogeneous mixtures of water + ethanol + 2-methoxy-2-methylbutane at 298.15 K and atmospheric pressure. These data were satisfactorily correlated by the Redlich-Kister polynomial. For the same mixtures, vapour-liquid equilibrium (VLE) data at 101.32 kPa were determined using a distillation apparatus recycling both liquid and vapour phases. The Wisniak-L-W and McDermott-Ellis tests confirmed these VLE data to be thermodynamically consistent, and they were satisfactorily correlated using the NRTL equation (with alpha=0.3), and satisfactorily predicted using the UNIFAC-Lyngby model to estimate the liquid-phase activity coefficients.