Polypropylene/Pine apple leaf fiber (PP/PALF)-reinforced nanocomposites were fabricated using melt blending technique in a twin-screw extruder (Haake Rheocord 9000). Variation in mechanical properties, crystallization behavior, water absorption, and thermal stability with the addition of nanoclay in PP/PALF composites were investigated. It was observed that the tensile, flexural, and impact properties of PP increase with the increase in fiber loading from 10 to 30 wt %. Composites prepared using 30 wt % PALF and 5 wt % MA-g-PP exhibited optimum mechanical performance with an increase in tensile strength to 31%, flexural strength to 45% when compared with virgin PP. Addition of nanoclay results in a further increase in tensile and flexural strength of PP/PALF composites to 20 and 24.3%, which shows intercalated morphology. However, addition of nanoclay does not show any substantial increase in impact strength when compared with PP/PALF composites. Dynamic mechanical analysis tests revealed an increase in storage modulus (E') and damping factor (tan delta), confirming a strong influence between the fiber/nanoclay and MA-g-PP. Differential scanning calorimetry, thermogravimetric analysis thermograms also showed improved thermal properties when compared with the virgin matrix. TEM micrographs also showed few layers of agglomerated clay galleries along with mixed nanomorphology in the nanocomposites. Wide angle X-ray diffraction studies indicated an increase in d-spacing from 22.4 angstrom in Cloisite 20A to 40.1 angstrom in PP/PALF nanocomposite because of improved intercalated morphology. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 4091-4103, 2009