In recent years, a number of papers have been published on advanced oxidation processes (AOP) demonstrating their effectiveness to destroy aqueous organic pollutants in contaminated groundwater or industrial wastewater. In this study, the liquid phase oxidation of phenol has been studied to evaluate the comparative effectiveness of five categories of oxidation processes, namely (i) photolysis with ultraviolet light radiation, (ii) hydrogen peroxide oxidation, (iii) hydrogen peroxide/Fe (II) oxidation (Fenton's reaction), (iv) UV/hydrogen peroxide oxidation, and (v) UV/hydrogen peroxide/Fe (II) oxidation (Photo-Fenton's reaction). The last three reactions are collectively called Advanced Oxidation Process (AOP). Under suitable experimental conditions, degradation of phenol by the three AOPs is high and nearly comparable. Photo-Fenton's reaction results in maximum conversion of phenol and destruction of the initial COD followed by the Fenton's reaction and UV/H2O2 reaction.