Liquid-liquid equilibria (LLE) data for the ternary system water + acetic acid + diisopropyl ether (DIPE) at (293.15, 303.15, and 313.15) K have been measured under atmospheric pressure. The reliability of the experimental LLE data was ascertained through the Othmer-Tobias and Bachman correlations. The LLE data were correlated using the nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models. The interaction parameters of those two models were regressed. The calculated values from both models agree well with the experimental values.