The polymer composites reinforced with ceramics materials have successfully replacing traditional materials in various applications. In this research, the properties of Polyethylene Terephthalate (PET) Polymer and Aluminum oxide (Al2O3) as reinforcement are investigated systematically. Both PET and Al2O3 powders were mixed homogeneously by ball milling and fabricated by injection molding machine as per ASTM standards. The outcome of Aluminum oxide (0–40 wt%) were investigated on the physical, mechanical, and Tribological properties. The distribution of Al2O3 particles in the matrix was analyzed by Optical microscopy, the results shown significant improvement in physical mechanical and Tribological properties. The microhardness, impact strength, and Tensile strength increased by 30% and 90%, 60% respectively, and percent elongation decreased, by 47%. The wear rate and Coefficient of friction also reduced. The results of PET/Al2O3 composites exhibit superior mechanical and Tribological properties. These properties show great potential materials for automotive, robotic, and food processing applications.