TiO2(B) nanowires (TiO2(B)‐NWs) were synthesized and characterized by X‐ray diffraction, and Scanning Electron Microscopy (SEM) micrographs and the influence of different morphologies of TiO2 nanostructures on the mechanical performance of epoxy nanocomposites were thoroughly investigated. Transmission Optical Micrograph images of TiO2(B)‐NW/epoxy nanosuspension reveals an excellent dispersion of TiO2(B)‐NWs in the epoxy matrix. Tensile strength (~26%), tensile modulus (~16%), and fracture toughness (~136%) improved remarkably for TiO2(B)‐NWs modified epoxy composites. The mechanism that paved way to the enhancement in the fracture toughness of the TiO2(B)‐NW/epoxy nanocomposites was evaluated. SEM micrographs disclose that the phenomena of shear yielding, crack deflection and crack bridging are responsible for the improved fracture toughness of TiO2(B)‐NW/epoxy composite. Moreover, the analysis of visco‐elastic properties revealed a very high modulus and improved Tg for the TiO2(B)‐NW/epoxy composites when compared with neat epoxy owing to better filler/matrix interfacial interaction between TiO2(B)‐NWs and epoxy matrix. This was further confirmed by quantitative analysis of the constrained region and by the evaluation of the interaction parameter B. TGA study shows that the thermal stability of composites are not compromised by the incorporation of TiO2 nanofillers. The obtained results can be considered as beneficial in the manufacture of components with higher strength‐to‐weight ratios for such uses as windmill blades or aircraft components. POLYM. COMPOS., 40:2629–2638, 2019. © 2018 Society of Plastics Engineers