Isobaric vapor-liquid equilibrium (VLE) data were measured for the systems tert-butanol-isobutanol and tert-butanol-water at 94.9 kPa using a modified Malanowski equilibrium still. While the experimental data of the former binary showed a slight deviation from ideality, the latter binary showed a significant deviation. The experimental data of this work, in addition to two isobaric VLE data sets from the literature, have been analyzed using Wilson, NRTL, UNIQUAC, ASOG, and the modified UNIFAC models. Optimum interaction parameters, together with their correlation coefficients, for the first three models were generated using the maximum likelihood principles, As to the group contribution models (ASOG and UNIFAC), interaction parameters from the literature were utilized in the data analysis. A comparable correlation of the experimental data was obtained for the first three models; the maximum values of Root-Mean-Square-Deviation (RMSD) of bubble point temperatures and vapor mole fractions were 0.24 K and 0.044, respectively (using NRTL). ASOG and the modified UNIFAC gave similar predictions; the maximum RMSD of bubble point temperatures was found to be 0.7 K whereas that of vapor mole fractions was 0.022.