AbstractHybrid composites of polyethylene/wood flour/nanoclay with different concentrations of nanoclay were fabricated using melt compounding followed by injection molding. Composites were weathered in a xenon-arc type accelerated weathering apparatus for 2000 h. Physical properties of the composites were evaluated by colorimetery and water absorption before and after weathering. Changes in surface chemistry were monitored using spectroscopic techniques. The results indicated that water absorption of the composites increased after weathering, but nanoclay can reduce the intensity of weathering to some extent by decreasing water absorption. Weathering increased the degree of color change and lightness of the samples; however, the lightness of the samples containing nanoclay was less than that of neat wood-plastic composites. Fourier transform infrared spectroscopy revealed a lower carbonyl index of composites containing nanoclay. X-ray diffraction patterns revealed that the nanocomposites formed were intercalated. The order of intercalation for samples containing 2 wt% nanoclay was higher than that of 4 wt% at the same maleic anhydride grafted polyethylene content, due to some agglomeration of the nanoclay.