The manufacture of carbon fibers includes an oxidative electrochemical process that represents an untapped source of potential surface manipulation beyond simple installation of oxygen containing functional groups. In this work we show that applying an oxidative treatment, at much lower oxidative potentials (+1.75 V) compared to industry standards, can result in simultaneous surface modification and oxidation resulting in substantial increases in interfacial shear strength, up to 112%, relative to pristine carbon fibers. The optimal treatment window for this process is 10 min, offering synergistic oxidation and surface grafting interactions with epoxy resin. This treatment is easily scalable, amenable to a continuous oxidation process, and can be adapted to existing infrastructure currently used in carbon fiber manufacture.