Liquid-liquid equilibrium data of the system composed by soybean oil, fatty acid methyl esters (FAMEs), methanol, and glycerol were experimentally determined at temperatures of 25, 45, and 65 degrees C. Three binary systems (oil + methanol, oil + glycerol, and FAMEs + glycerol) and all the ternary combinations were evaluated. With these data, universal quasichemical (UNIQUAC) and non-random two-liquid (NRTL) binary interaction coefficients were calculated and validated. According to the results, the UNIQUAC model fitted the experimental data better than the NRTL one. In order to complete this study, UNIQUAC binary interaction coefficients for the mixtures of oil, FAMEs, methanol, and glycerol with monoglycerides and diglycerides were also predicted using a group contribution model (universal quasichemical functional-group activity coefficients) and checked using experimental data from the soybean oil transesterification reaction.