Natural fibers fulfill most requirements needed to replace synthetic fibers in thermoplastic composites. However, some disadvantages appear when natural fibers are used for composites. The poor compatibility between the hydrophilic fibers with the hydrophobic thermoplastic matrix leads to a weak interface and hence, poor mechanical properties. In this work, the effects of processing techniques (fiber surface modification and varying compounding pressure) on the mechanical properties of rice husk-polypropylene composite were investigated. The results showed improvement in mechanical properties for the treated composites (tensile strength, impact energy and hardness), with the mercerized sample having the highest improvement. The trend of results suggest that there is a need for further work on the optimization of the fiber-matrix interface for improved mechanical properties to be achieved. © 2011 IEEE.