The incorporation of natural fibers as a reinforcing agent in thermoplastic polymer composites has gained increasing applications both in many areas of engineering and technology. Several natural fiber-based thermoplastic composite materials have been developed using modified synthetic strategies to extend its application in the automotive area. The advantage of using natural fibers is more economical and ecologically favorable. The effects of the incorporation of natural fibers in petrochemical-based thermoplastic matrixes were extensively studied. Polypropylene (PP), polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), thermoplastic polyurethane (TPU), polyamide (PA), and acrylonitrile butadiene styrene (ABS) were used for thermoplastic matrices. High performance thermoplastic matrices such as polyamides instead of the commonly used polyolefins were used to develop natural fiber composites for substituting glass fibers without renouncing their mechanical properties. Flax, jute, pure cellulose, and wood pulps have been melt compounded with different polyamides to analyze the effect of fiber content on mechanical properties.