The structural, optical, morphological and thermal properties of poly (methyl methacrylate) (PMMA)/boehmite nanocomposite films were studied by Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) studies. The FT-IR spectra of composites showed the characteristic band of boehmite nanoparticles at 518 cm−1 indicating an effective interaction between PMMA and boehmite. The UV-visible measurements showed that the optical energy gaps for the direct permitted transitions decreased as boehmite content increased. The orientation of nanoparticles observed from XRD revealed that the addition of boehmite increases the crystallinity of PMMA. The SEM analysis showed the uniform distribution of boehmite in the PMMA matrix. The shift in glass transition and melting temperatures to higher temperature domains were revealed by DSC analysis. From the TGA studies, the reinforcement of PMMA with boehmite nanoparticles increases thermal stability. The electrical conductivity was measured using the impedance technique, and it was studied as a function of nanoparticles loading, applied frequency ranging from 100 to 106 Hz and at different temperatures. The AC conductivity of the composite increases with frequency and temperature. The activation energy was also measured for all samples at various applied frequencies, and it was observed that it decreased with increasing nanoparticle loading. The dielectric constant of PMMA increases with nanoparticle concentration up to 7 wt%. The modulus, tensile strength, hardness, and impact properties of the PMMA/boehmite nanocomposite films were significantly enhanced by the reinforcement of nanoparticles into the polymer matrix. The excellent optical properties, mechanical strength and electrical properties obtained for 7 wt% loaded nanocomposite films enable them to be used in the construction of electromagnetic induction shielding materials, conducting adhesives, and flame-resistant flexible optoelectronic devices.