The paper studies the influence of compatibilizer (polypropylene-graft-maleic anhydride, PP-g-MA) on morphology and mechanical properties of polypropylene/zinc oxide composites. Polypropylene (PP) and zinc oxide (ZnO) composites were prepared by melt mixing technique in a twin screw extruder. The Young's modulus and impact strength of the composites increased as ZnO loading increased, but the impact strength was decreased with the addition of the compatibilizer. The tensile strength of the composites before and after adding compatibilizer was almost the same with the pure PP. The dispersion of ZnO in the matrix polymer was investigated using scanning electron microscope (SEM). The results obtained show that the addition of a small of PP-g-MA compatibilizer during melt extrusion improved the dispersion of ZnO particles.