The free radical-induced grafting of maleic anhydride (MA) onto syndiotactic polystyrene (sPS) has been accomplished in the solution process by using 1,1,2-trichloroethane as solvent and dicumyl peroxide as free radical initiator. The amount of MA grafted on sPS was evaluated by a titration method. Grafted products separated from the reaction mixture were purified and analyzed. Fourier transform infrared spectroscopy and H-1 NMR studies indicate that MA attaches to the sPS in the form of single succinic anhydride rings as well as short oligomers. The results obtained by GPC analysis suggest that the degradation and chain extension reaction do not occur under the reaction conditions. Moreover, the crystallization behavior of MA-functionalized sPS was also studied by means of differential scanning calorimetry. It was found that the crystallization behavior of the grafted polymer exhibited somewhat differences in comparison to the neat sPS. The MA-functionalized sPS crystallizes at higher rate than the unmodified polymer, on the other hand, the degree of crystallinity (X-c) are lowered by the presence of the MA grafts.