A brief review of data on solubility and liquid-liquid equilibrium (LLE) in the acetic acid – ethanol – ethyl acetate – water system is presented. A new set of experimental data on solubility, LLE, and critical phases in this quaternary system, ternary subsystems (acetic acid – ethyl acetate – water, ethanol – ethyl acetate – water) and binary subsystem ethyl acetate – water are presented for 323.15 K and 333.15 K at atmospheric pressure. The gas chromatography and the cloud point technique were used to obtain experimental data. Binodal curves, surfaces, and critical manifolds are presented including 3D phase diagrams in composition tetrahedron. Experimental LLE data were correlated using the NRTL model.