The present work investigates the mechanical properties of surface-modified magnesium alloy AZ61 reinforced with Al2O3 and TiO2 nanoparticles by using the friction stir processing (FSP) technique. Surface-modified AZ61 alloys were fabricated by the addition of dufferent amount of Al2O3 and TiO2 nanoparticles (5, 10, and 15 vol.%). The developed surface composites were studied regarding microstructure, revealing a uniform dispersion of the added nanoparticles, which resulted in improved mechanical properties of the obtained composites by FSP. The ultimate tensile strength, impact strength, and microhardness improved by 20, 45, and 67 % by reinforcing the alloy with nanoTiO2 particles when compared to the as-cast alloy. The results of this study indicate that the reinforced AZ61 Mg alloy can be a potential material for applications in automobile sectors due to its high strength and lightweight components.