Wood polymer composite (WPC) were developed by using solution blended high density polyethylene, low density polyethylene, polypropylene, poly(vinyl chloride), Phragmites karka wood flour and polyethylene-co-glycidyl methacrylate. The effect of addition of nanoclay and SiO2 on the properties of the composite was examined. X-ray diffractrometry and transmission electron microscopy were used to study the distribution of silicate layers and SiO2 nanopowder in the composite. The improvement in miscibility among the polymers and WPC was studied by scanning electron microscopy. Fourier transform infrared spectroscopy study revealed the interaction between polymer, wood, clay and SiO2. WPC treated with 3 wt% each of clay and SiO2 showed an excellent improvement in mechanical properties, thermal and flame retarding properties. Water uptake of WPC was found to decrease on incorporation of nanoclay and SiO2 in WPC.