Rice straw is causing in many countries severe environmental problems in terms of black clouds caused by the incineration process. Hence, among other reasons, the incorporation of ground rice straw as a filler and reinforcement material for polymers is of advantageous. In this study, Egyptian rice straw was used to reinforce commercial polypropylene and laboratory prepared maleic anhydride-grafted PP with the fill grades between 5wt% and 30wt%. Rice straw PP composites show an improved Young's modulus at increased fill grades, against a decrease in tensile strength. The addition of 1% maleic anhydride per I g of rice straw as a compatibilizing agent caused further amelioration of the fiber/matrix bonding leading to improved mechanical behavior, which was also assessed using scanning electron microscopy. Additional assessments were made via thermographic analysis and density measurements.