Transparent poly(methyl acrylate-co-itaconic anhydride)/SiO2 hybrid materials were prepared from methyl acrylate-itaconic anhydride copolymer and tetraethoxysilane (TEOS:) with the coupling agent (3-aminopropyl)triethoxysilane (APTES) via a sol-gel process. The covalent bonds between the organic and inorganic phases were introduced by the in situ aminolysis of the itaconic anhydride units with APTES forming a copolymer bearing a triethoxysilyl group. These groups subsequently were hydrolyzed with TEOS and allowed to form a network. These reactions were monitored by Fourier transform infrared analysis. The amount of APTES had a dramatic influence on the gel time and sol fraction. The effect of APTES, the inorganic content, and the nature of the catalyst on the thermal properties and morphology of the hybrid materials were studied by differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, and atomic force microscopy.