Advanced Oxidation Processes (AOPs) have been developed as an emerging technology for treating hazardous organics in wastewater and groundwater. In the present study, the effect of oxidants peroxomonosulphate and peroxodisulphate on the photocatalytic oxidation of catechol on illuminated TiO2 surfaces has been investigated. The efficiencies of these oxidants on photocatalytic degradation of catechol are compared with that of peroxomonosulphate and peroxodisulphate. The experimental results indicate that these oxidants exhibited enhanced rates of mineralization of catechol. A reaction mechanism, involving the generation of both hydroxyl radicals and sulphate radicals, was proposed.