Natural fibers have become an important issue in the development of fiber reinforced polymer (FRP) composite to resolve the current ecological and environmental problems. Among the many types of natural fibers that are available, pineapple leaf fiber (PLF) was selected as the natural fiber used in this study due to comparatively better mechanical properties, ease of availability and low cost. In this work, the effects of pineapple leaf fiber (PLF) loading on the properties of PLF/polypropylene (PP) composites was studied. The sample of composites was fabricated with five different fiber loading of PLF (30, 40, 50, 60 and 70 wt.%). An alkaline treatment was conducted to enhance the PLF properties. The fabrication was made by compression molding technique with random orientation of PLF. From the experimental study, the results revealed that the voids percentage and interfacial bonding between the PLF and PP affected the mechanical properties of the PLF/PP composite. Based on the results of tensile stress, hardness and density, it can be concluded that the PLF/PP composite with the composition ratio of 30/70 wt.% has shown the best mechanical properties compared to other composition ratios (40/60, 50/50, 60/40 and 70/30 wt.%), which are 16.71 MPa, 62.83 Shore-D and 0.93 g/cm³ respectively.