Although the water resource is not exhaustible, the water quality must be preserved. It does represent a major challenge for the coming decades. Since water is used for many different industrial, agricultural and domestic applications, a wide variety of waste effluents is being produced. Since conventional wastewater treatment plants, mainly based on biological processes, are poorly efficient for the treatment of toxic and/or non-biodegradable and/or highly concentrated effluents, new solutions are being looked for. Many different approaches have been investigated and catalytic processes may play a crucial role. Both oxidation and reduction processes for the treatment of chlorophenols have been reviewed. The principle of each of those processes is being described, the key parameters are identified and subsequently the major challenges to be overcome both in terms of material science and/or catalytic efficiency (activity and selectivity) are highlighted to offer a general but homogenized overview of the state-of-the-art in the different fields. Finally, the most recent developments in each field are shortly discussed.