Vapor liquid equilibrium (VLE) data of 1-methyl-2-ethylbenzene ( 1M2EB) + 1,2,4-trimethylbenzene (124TMB) at 10 kPa were measured by using a modified Rose Williams type recirculation still. The thermodynamic consistency of the VLE data was examined by the Herrington and Fredenslund methods. Experimental data were correlated by the Wilson, nonrandom two-liquid (NRTL), and universal quasichemical activity coefficient (UNIQUAC) models. All of the models were satisfactorily correlated with the VLE data. The result showed that the UNIQUAC model was slightly more suitable to correlate the experimental data and no azeotropic behavior was observed.