Interfacial strength between polymeric matrix and lignocellulosic reinforcement has direct effects on the properties of wood plastic composites (WPCs). There are two approaches to improve the interfacial adhesion between two phases in WPC: modification of the polymeric matrix or modification of the lignocelluloses fibres. This work focuses on the chemical modifications of natural fibres such as lignocellulosic, enhanced by silane, alkali, benzoyl chloride and acid acrylic. The chemically treated fibres were then compounded with polypropylene at 190°C and 40 wt%, in an internal mixer equipped with cam rotor, for all samples. Changes in the chemical structure of chemically treated fibres were tracked by Fourier transform infra red (FTIR) spectroscopy. The intensity of O-H bond at 3400 cm-1 and formation of ester bond at 1740 cm-1 were indications of changes in the chemical structure of the fibres. The interfacial adhesion was evaluated using adhesion factor which was obtained from dynamic mechanical thermal analysis data. The results showed that the minimum adhesion factor is related to silane treatment which provides the best interaction between polymer and fibres. The tan d peak was shifted to higher temperature for filled samples in comparison to neat polypropylene and the amount of shift was related to the method of chemical treatment. Different morphologies were observed in samples due to different chemical modifications of fibers and among them, silane treatment method of the fibers provides the best wetting action by polymeric matrix. Tensile properties and impact resistance of the samples were determined to evaluate the effect of interfacial adhesion on the performance of the composites.