Isobaric vapor-liquid equilibria (VLE) were measured for the system o-xylene + nonane + cyclohexanol and for two constituent binaries containing cyclohexanol at the pressures 26.66, 53.33, and 79.99 kPa. The new modified Wilson equation is proposed to better describe vapor-liquid equilibria (VLE) in binary and multicomponent systems. The equation takes into account the linear dependence of the difference of interaction energies lambda(ij) - lambda(ii) on temperature and avoids the use of molar volumes. Correlation of binary isobaric VLE experimental data gave four coefficients that can describe VLE at different pressures and in a large boiling temperature region. It was found that VLE data for the ternary system o-xylene + nonane + cyclohexanol can be predicted by the modified Wilson equation.