Materials that are low cost and lightweight are essential for future automotive and aerospace industries. While carbon fibers have been shown to achieve high mechanical properties for high-end applications, their high cost has generated interest to find cost-effective alternatives. The recent advances in recycling carbon fibers has created an opportunity to develop low cost composite materials. Using a maleic anhydride grafted polypropylene (MA-g-PP), the interfacial adhesion between the polypropylene (PP) matrix and the recycled carbon fibers is greatly improved. The integration of 20 wt% recycle carbon fibers result in 2.4 times, 4.9 times, and 5.7 times enhancements in tensile strength, notched Charpy impact strength, and flexural modulus, respectively. This enhancements in mechanical properties are significantly higher than those reported in previous works. The addition of recycled carbon fibers also increases the heat deflection temperature (HDT) of the neat PP sample, indicating the higher resistance of the composite samples at high temperature. This work demonstrates the great potential of the recycled carbon fibers in manufacturing cost-effective and high-performance PP composites.