Abstract Polypropylene (PP) based hybrid composites with treated hollow glass microspheres ( t -HGM) as inorganic low density filler and naturally sourced bamboo fibers for strength reinforcement are prepared. The hybrid composites may fulfill the need for potential light-weight and high-strength modern engineered materials required for automotive and aerospace industry applications. The interfacial adhesion between different filler-matrix interfaces such as fiber-PP and t -HGM-PP has been enhanced by using maleic anhydride-grafted polypropylene (MA-g-PP). PP and MA-g-PP taken in a 9:1 ratio constitute the base matrix (BM), while the bamboo fiber is varied from 0 to 20 wt% keeping the HGM loading fixed at 10 wt% with respect to BM. While a density reduction of ∼8.5% is achieved by addition of HGM's, the decrease in mechanical strength has been more than compensated by the added bamboo fibers. Interestingly, for 20 wt% fiber addition the tensile, flexural and impact strengths increased by 23.5%, 38.5% and 47.9%, respectively, over and above the virgin PP values. The morphological studies via SEM showed good wetting of both fillers without any signs of aggregation and hindrance to each other's property contribution. The work paves the way for engineering and design of components based on other promising light-weight high-strength natural fiber based composites.