The paper presents a comprehensive kinetic model that describes the degradation of methyl tert-butyl ether (MTBE) in an ozone/UV process. First, the degradation pathways for MTBE were proposed on the basis of major reaction intermediates identified during the oxidation of MTBE. The yield for each major reaction intermediate was determined by fitting experimental data to the model prediction. Accordingly, 43, 20, 15, 11, and 6% of MTBE oxidized resulted in the generation of TBF, MMP, TBA, acetone, and methyl acetate, respectively. TBF oxidation resulted in the generation of HiBA, acetone, and TBA as primary intermediates at 47, 24, and 20%, respectively. During the oxidation of TBA, 66% resulted in the generation of HiBA and 34% in acetone. The kinetic model was verified using different sets of experimental data by varying the initial concentration of MTBE, influent ozone gas concentration, and incident UV light intensity. The model predicted well the degradation of MTBE by an ozone/UV process. In addition, the model predicted the accumulation and decay of primary intermediates (TBF, TBA, MMP, methyl acetate, and acetone) with slight variations.