Isobaric vapor-liquid equilibrium (VLE) data for the binary systems of acetic acid + acetylacetone and water + acetylacetone have been determined at 101.3 kPa, and those for the acetic acid + isopropenyl acetate system have been determined at 60.0 kPa. A minimum boiling azeotrope has been found in the water + acetylacetone system. Azeotropic behavior has not been found for the other two systems. The nonideality of the vapor phase has been considered by using the Hayden-O'Connel I equation. Thermodynamic consistency has been tested for all VLE data. The experimental data have been correlated satisfactorily by the NRTL, UNIQUAC, and Wilson models.