The solubility and liquid-liquid equilibrium (LLE) data were measured for the ternary system methanol + acrylonitrile + water at 288.15 K, 298.15 K, and 313.15 K and atmospheric pressure. The quality of the experimental tie-line data has been checked by Hand and Othmer-Tobias correlations. The nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models were applied to correlate the experimental data, and the interaction parameters for both models were regressed with an overall root-mean-square deviation (rmsd) less than 0.32%. Selectivity values of water for methanol at the studied temperatures are within the range 1.5 < S < 26.5. The effect of temperature on the miscibility gap and the selectivity of water for methanol is minor.