Crystallization kinetics were characterized by using isothermal differential scanning calorimetry (DSC) analysis on neat semicrystalline syndiotactic polystyrene (s-PS) and its miscible blends with atactic (amorphous) polystyrene (a-PS) or with poly (1,4-dimethyl-pphenylene oxide) (PPO). The crystallization behavior of neat s-PS polymer was compared to its miscible blends. The results suggest that the crystal growth in melt-crystallized s-PS is nearly of homogeneous nucleation and that the growth pattern of the spherulites is 3-D spherical. The s-PS component in its miscible blends was found to crystallize with similar behavior to that of neat s-PS, but with lower Avrami exponents, suggesting that the nucleation mechanism is likely more heterogeneous with blending.