In this study, it was aimed to synthesize and characterize UV and thermally curable polybenzoxazine/silica nanocomposites as high performance coating materials. For this purpose, synthesis and characterization of allyl-functional benzoxazine monomers and thiol-functional silica nanoparticles were performed to carry out UV polymerization. Allyl functional benzoxazine monomers were characterized by FT-IR (Fourier Transform Infrared) and H-1 NMR (Nuclear Magnetic Resonance) spectroscopy techniques. Using the obtained benzoxazine monomers and silica nanoparticles, polybenzoxazine/silica nanocomposites in various formulations were prepared by UV and thermal curing. Structural characterization of prepared nanocomposites were analyzed by FT-IR spectroscopy technique. The thermal and mechanical properties of the nanocomposite films were analyzed by TGA/DTA (Thermogravimetric Analysis/Differential Thermal Analysis) and DMA (Dynamic Mechanical Analysis). Morphological structures were investigated by SEM (Scanning Electron Microscopy) and particle distributions were investigated by EDS (Energy Dissipative X-Ray Spectroscopy). In addition, gel contents and water absorption capacities of the samples were determined. It was determined that thiol functional nanosilica reinforcement increased the thermal and mechanical strength of nanocomposite films and the optimum amount of thiol functional nanosilica to be added at room temperature was 1 mmol. When all the results obtained were evaluated, it was concluded that nanocomposite films with superior thermal and mechanical properties that could be used in the coating industry were produced.