Oxidative degradation of phenol by H2O2 and ultraviolet radiation is carried out, and a kinetic model is derived in order to represent the photooxidation reaction. The model equations are fitted by the experimental data collected for two distinct phases of reaction, marked as phase I and phase II. In the first phase H2O2 concentration is the controlling factor in the degradation process, whereas in the second phase concentration of phenol is the controlling species. A mechanistic explanation of the behavior has been presented.