Reduced graphene oxide exhibits high activity as Fenton catalyst with HO. radical generation efficiency over 82 % and turnover numbers of 4540 and 15023 for phenol degradation and H2O2 consumption, respectively. These values compare favorably with those achieved with transition metals, showing the potential of carbocatalysts for the Fenton reaction. Graphene makes degrade: Graphenes are highly efficient metal‐free carbocatalysts for the generation of hydroxyl radicals in water. Reduced graphene oxide exhibits high activity as a Fenton catalyst with HO. radical generation efficiency of over 82 % and turnover numbers of 4540 and 15023 for phenol degradation and H2O2 consumption, respectively.