Poly(ethylene terephthalate) (PET)/antimony-doped tin oxide (ATO) nanocomposites were prepared by in situ polymerization. The nonisothermal crystallization behaviors of neat PET and PET/ATO nanocomposites were investigated with differential scanning calorimetry. The nonisothermal crystallization data were analyzed with the Avrami analysis modified by Jeziorny, the Ozawa method, and a method developed by Liu et al. The modified Avrami equation could describe only the primary stage of nonisothermal crystallization of PET and PET/ATO nanocomposites. The Ozawa analysis, when applied to the polymer systems studied here, failed to describe their nonisothermal crystallization behavior. The kinetic method developed by Liu et al. was successful in describing the nonisothermal crystallization of neat PET and PET/ATO nanocomposites. According to the Kissinger equation, the activation energies were determined to be -205.3, -220.0, and -243.7 kJ/rnoI for neat PET and 99/1 and 95/5 PET/ATO nanocomposites, respectively. 9) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 109: 3753-3762,2008.