This work presents densities, viscosities, interfacial tensions, and liquid-liquid equilibrium data for systems of interest in vegetable oil refining and biodiesel production, composed of soybean oil + commercial cis,cis-octadeca-9,12-dienoic acid (linoleic acid) + ethanol + water at 298.2 K with water mass fractions in the alcohol solvent (ethanol + water) of 0.05, 0.08, 0.11, and 0.14. Experimental phase compositions at equilibrium were correlated using the nonrandom two-liquid (NRTL) model. For all systems, the global deviations between calculated and experimental phase compositions were no greater than 0.0005. All physical properties were evaluated by empirical correlations as functions of phase compositions. The absolute relative deviations between calculated and experimental data were no greater than 6.36 To. Water content in the solvent presented a considerable effect on the physical properties of the systems and phase compositions at equilibrium, even more so on its interfacial tensions.