To meet current requirements for the development of novel materials possessing high specific properties and low environmental impact, this paper deals with the study of the incorporation of hollow glass microspheres (HGM) and piassava fibers into homo- (PPH) and co-polypropylene (PPC) matrices. Various compositions of HGM/piassava fiber-reinforced PP composites were extruded and injection molded to obtain their rheological, mechanical and morphological properties. The formulation with 60 wt% of PPC or PPH, 20 % wt of coupling agent, 5 wt% of HGM and 15 wt% of piassava fiber reached the highest tensile and flexural modulus for both PPH- and PPH-based composites. Furthermore, the PPC-60/20/5/15 composition presented flexural strength higher than that of the neat PPC. Morphological analysis revealed that the incorporation of the coupling agent enhanced adhesion between mineral filler and piassava fiber embedded into PPH or PPC matrices.