Metal-free carbon materials can provide an alternative to replace the traditional metal-based catalysts used in Catalytic Wet Air Oxidation (CWAO). The discovery and synthesis of novel carbon allotropes (carbon nanofibers, nanotubes, graphene-based materials and nanoporous carbon gels) encouraged the investigation of their potential to promote the oxidation of organic compounds by CWAO. This short review presents the progress made in the use of those nanocarbons as catalysts in CWAO.