In this study, we examined the effect of vanadium pentoxide (V(2)O(5)) on the mechanical, thermal, and morphological properties of poly(vinyl alcohol) (PVA)/V(2)O(5) nanocomposites. The PVA/V(2)O(5) nanocomposites were prepared by solution mixing, followed by film casting. The results show that the Young's moduli of the resulting nanocomposites films were higher than the pure PVA modulus with increasing V(2)O(5) content, and it reached a maximum point at about 0.4 wt % V(2)O(5) content at 8.55 GPa. The tensile strength and stress at break increased with increasing V(2)O(5) content. The addition of V(2)O(5) did not affect the melting temperature. The crystallization temperatures of PVA were significantly changed with increasing V(2)O(5) content. The 5% weight loss degradation temperature of the nanocomposites was measured by thermogravimetric analysis. The degradation temperatures of the V(2)O(5) nanocomposites increased with increasing filler content and were higher than the degradation temperature of pure PVA; this showed a lower thermal stability compared to those of the nanocomposites. The results show that the thermal stability increased with the incorporation of V(2)O(5) nanoparticles. The dielectric constant of PVA had a tendency to improve when the dispersion of particles was effective. The morphology of the surfaces the nanocomposites was examined by scanning electron microscopy. We observed that the dispersion of the V(2)O(5) nanoparticles was relatively good; only few aggregations existed after the addition of the V(2)O(5) nanoparticles at greater than 0.4 wt %. In perspective, the addition of 0.4 wt % V(2)O(5) nanoparticles into PVA maximized the mechanical, thermal, and electrical properties. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 2870-2876, 2011