In this study, a novel experimental approach was used to overcome the lack of phase equilibrium information to obtain data that is more applicable to industrial situations. Liquid–liquid equilibrium (LLE) data, tie-lines, and phase boundaries were carried out for two systems of canola oil methyl esters (containing 1 wt % KOH) + glycerol + methanol and sunflower oil methyl esters (containing 1 wt % KOH) + glycerol + methanol at three different temperatures (303.15, 313.15, and 323.15 K). The quality of data was also ascertained using Othmer–Tobias correlations. The experimental LLE data was also correlated by the nonrandom two-liquid (NRTL) and the Wilson–NRF Gibbs free energy models. The energy interaction parameters of both models were obtained for both systems. The results indicated that the Wilson–NRF provided an accurate correlation of LLE behavior with average absolute deviation (AAD%) inferior to 8.78% and 10.80% for canola and sunflower biodiesel systems, respectively. However, the NRTL model prese...