The current investigation is focused on the fabrication and characterization of Al2O3reinforced AZ91 Magnesium (Mg)matrix composites. These lightweight and wear-resistant composites were developed by incorporating the varying Al2O3reinforcement in weight percentages (wt% ages) into AZ91 Mg matrix alloy using stir casting technique in conjunction withultrasonic agitations with optimal conditions. The effects of varying wt% of reinforcements on the composite’s particledistribution, matrix-particle interfacial reaction, microstructure, mechanical and tribological attributes were investigated. The tribological performance of base matrix alloy and the developed composites was examined using a friction and wearapparatus. The analysis using SEM, OM, and XRD were accomplished to investigate the surface morphology, microstructure,and phase changes of base matrix alloy and the developed composites. The mechanical characterization shows that theinsertion of Al2O3particulates prompted the simultaneous enhancement in microhardness, impact strength, and indentationfracture toughness. The homogeneous dispersion of fine particles caused by the ultrasonic agitations was credited withimproving wear resistance. The wear tracks were formed on the worn specimen by adhesion, oxidation, erosion of soft AZ91magnesium matrix, and the delamination when assessing sliding wear, as revealed by the micro-structural investigation. The eruption of base matrix and the pull-out of the particles have both contributed to the material removal. The addition ofreinforcement above a certain limit led to the agglomeration, clustering, and uneven distribution of particles, which resultedin the deterioration in impact toughness and the wear-resistance of the composite.