Isobaric vapor liquid equilibrium (VLE) data for the tert-butyl alcohol (t-BuOH) + water + triethanolamine (TEA), t-BuOH + water + triethanolamine formic acid ([TEA][Fc]), t-BuOH + water + triethanolamine acetic acid ([TEA][Ac]), and t-BuOH + water + triethanolamine lactic acid ([TEA] [Lc]) ternary systems were measured at 101.3 kPa. The results indicated that all the three ILs produced a more obvious effect on the VLE behavior of t-BuOH + Water system than TEA, and eliminated the azeotropic point in the whole concentration range. [TEA] [Lc] was the hest solvent for the separation of the t-BuOH + water system by extractive distillation among the three ILs investigated. The experimental VLE data for the ternary systems were correlated with the NRTL model equation, and good correlations were obtained with an average relative deviation of 2.4 %.