The present study focuses on the influence of the PEO (Plasma Electrolytic Oxidation) treatment on the tribological behaviour of the AA2618/20 % vol. Al2O3p composite, dry sliding against induction hardened UNI C55 steel. Particle-reinforced Al based composites offer a higher wear resistance by comparison with the corresponding unreinforced alloys, however, the presence of critical loads and/or velocities which lead to transition towards severe wear regime, was often observed. In such conditions, the composite can show higher wear rates than those of unreinforced alloys. For this reason, surface modifications, such as PEO, might contribute to improve wear resistance. In this paper, topography, microstructure, phase constitution and surface hardness of the PEO-treated composite were investigated and its tribological behaviour was studied by dry sliding tests using a block-on-ring tribometer. The results were compared with those from the uncoated composite, demonstrating a very positive effect of the PEO treatment, which moved transitions from mild to severe wear towards more severe test conditions, in terms of both load and velocity.