We measured the liquid-liquid equilibrium and obtained the tie lines for the ternary systems of (water + acetone) and either cumene or alpha-methylstyrene or phenol at two temperatures of (323.15 and 333.15) K, at a pressure of 0.1 MPa. The NRTL model and the UNIQUAC model were fit to the experimental results in order to obtain interaction parameters for the components. The standard deviations of the calculated values from the experimental results were in the range (0.0026 to 0.0081). The UNIFAC model, based on group contribution, was also employed to describe the equilibrium conditions. For this model, the standard deviations were in the range (0.015 to 0.079) for these mixtures.