The effect of gamma radiation on the morphology, thermal behavior and mechanical properties of wood polypropylene composites has been investigated. Simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) have been performed on wood polymer composite (WPC) samples of 9.5 ± 0.1 mg. These samples were exposed to different gamma dose in the range 10–100 kGy. The results indicated that gamma radiation improves the mechanical properties while the thermal stability is decreased. With gamma radiation, the scanning electron microscopy (SEM) of the micrographs became smoother and we can notice an improvement of interaction between polymer and wood fibers.