The investigations on the non-isothermal crystallization kinetic behavior have been conducted by means of differential scanning calorimeter. The Avrami, Ozawa, and combined Avrami and Ozawa equations were applied to describe the crystallization kinetics and to determine the crystallization parameters of the alumina-filled PEEK nanocomposites. It is found that the inclusion of the nano-sized alumina particles can accelerate the nucleation rate due to heterogeneous nucleation but reduce the growth rate due to retarded polymer chain mobility. The resulting crystal grain size appears to be smaller in the nanocomposites. On the other hand, the nanocomposites show a higher Avrami value than that of the neat PEEK, implying a more complex crystallization configuration. Moreover, the combined Avrami and Ozawa equation can successfully describe the crystallization model under the non-isothermal crystallization. (c) 2005 Elsevier B.V. All rights reserved.