This work demonstrates the effect of poly vinyl alcohol modified ZnO nanoparticles on thermal and mechanical properties of epoxy nanocomposites. Modified ZnO nanoparticles with controlled particle size were successfully synthesized by sol-gel method. The surface modification of nanoparticles was confirmed by FT-IR, EDX and TGA analysis. Epoxy nanocomposites were prepared using different wt% (0 3 wt%) of unmodified and modified ZnO nanoparticles. A significant improvement in T-g was achieved for synthesized epoxy nanocomposites. The dispersion and interfacial interactions between unmodified (ZN) and PVA modified ZnO (PZN) with the epoxy matrix were investigated by morphological study of fractured surface of epoxy nanocomposites. The improvement in mechanical performance of PVAassisted ZnO nanoparticle reinforced epoxy composites was found superior at 2 wt% of particle concentration. The maximum enhancement in mechanical properties such as tensile strength, tensile modulus, compressive strength, flexural strength and flexural modulus was similar to 24, 47, 48, 44 and 77% respectively with respect to that of neat epoxy system. We have exposed the potential of the PVAassisted ZnO nanoparticle as good choice of reinforcement for composite industries. (C) 2017 Elsevier B.V. All rights reserved.