Isothermal vapor-liquid equilibrium (VLE) data were measured for binary systems of l-octanol + 2-methoxyphenol and 1-octanol + 1,2-dimethoxybenzene and a ternary system of 1,2-dimethoxybenzene + 2-methoxyphenol + 1-octanol at temperatures from 433 to 463 K. Maximum pressure azeotropes appeared in all three systems. Three correlative solution models were utilized in data reduction. Moreover, new group-interaction parameters of the UNIFAC model were determined from binary VLE data for several aromatic methoxyl (Ac-OCH3) binaries. The group-interaction parameters were tested with VLE data of ternary systems.