Isothermal vapor-liquid-liquid equilibrium data were measured for the ethanol + water + diethyl carbonate (DEC) ternary system and the constituent binaries using static headspace gas chromatography (HSGC) at 353.15 and 363.15 K. Multiple headspace extraction was used to calibrate the gas chromatograph. The activity coefficients were calculated using the Gibbs-Duhem equation and thermodynamic correlations. The thermodynamic consistency of the experimental vapor-liquid and vapor-liquid-liquid equilibrium data was verified. The experimental data were correlated using NRTL and UNIQUAC models, obtaining new UNIQUAC and NRTL interaction parameters for the VLE and VLLE. (C) 2012 Elsevier B.V. All rights reserved.