Using free radical polymerization process a series of samarium-doped titanium dioxide (Sm 3+ -doped TiO 2 ) nanoparticles containing poly (n-butyl methacrylate) (PBMA) composites were synthesized. The fabricated samples were characterized by XPS, FTIR, UV, XRD, DSC, TGA, flame retardancy studies, and impedance analyser. The shift in FTIR peak of the nanocomposites to higher wavenumber indicates the interfacial interaction between nanoparticles and PBMA. The UV spectra indicated that the metal oxide nanoparticles could enhances the interfacial interaction in the polymer composites. SEM images showed the uniform dispersion of nanoparticles into the macromolecular chain of PBMA. XRD patterns of the composites indicated the ordered arrangement of nanoparticles within the polymer and the regularity of the chain improved by the increase in concentration of nanoparticles. Better flame resistance and thermal stability were attained by the addition of nanoparticles. The flame retardancy and thermal stability of the composites were improved with the increase in concentration of Sm 3+ -doped TiO 2 . The glass transition temperatures of the composites were much enhanced by the increase in weight percentage of nano-filler. The AC conductivity, dielectric constant and dielectric loss tangent of the composites were higher than the pure PBMA and these properties enhanced with the loading of nanoparticles up to 7 wt.% and thereafter the values decreases.