Liquid-liquid equilibria of the ternary system water + acetic acid + methyl tert-butyl ether were studied from 293.15 K to 318.15 K at atmospheric pressure. Distribution coefficients and separation factors were evaluated for the immiscibility region. The reliability of the experimental tie-line data was ascertained by applying the Othmer-Tobias correlation. The experimental results were also correlated with the NRTL and UNIQUAC models successfully.