Oil palm empty fruit bunch-polypropylene (EFB-PP) composites were produced by employing 2 types of compounding techniques, that is, an internal mixer and a single-screw extruder. The mechanical and water absorption properties of both types of composites were investigated. Overall, for both types of composites, the incorporation of the EFB into PP matrix has resulted in the improvement in the tensile modulus. However, the tensile strength, elongation at break, and impact strength decreased with increasing filler loading. Poor filler-matrix interaction or compatibility and, also, the size irregularity of the EFB are believed to be responsible for the poor ultimate performance. Composites produced by an internal mixer (IM) have displayed higher tensile strength, tensile modulus, and impact strength than with those produced by extrusion (EX). The better performance has been attributed to the effectiveness of the IM, which produces better compounding and improves the wetting of the filler surface. Incorporation of compatibilizer and coupling agent, that is, Epolene wax (E-43) and 3-Aminopropyl triethoxysilane (3-APE), respectively, have produced composites with improved tensile strength for both EX and IM composites. In addition, both types of treatment have resulted in an increase in tensile modulus of EX composites and impact strength of IM composites. Water absorption tests have revealed that the presence of coupling agents and compatibilizers have affected the amount of water absorbed, especially for the 3-APE-treated EFB-PP composites.