AbstractThe kinetic parameters of the thermal decomposition of poly(aryl‐ether‐ether‐ketone) (PEEK) in a nitrogen atmosphere have been obtained using an isothermal weight‐loss method. Several mathematical approaches have been used to obtain the Arrhenius parameters based upon the use of different reaction models. The values obtained for the activation energy (E= 198.4 to 219.7 kJ/mol) and preexponential factor (logA= 11.1 to 12.3 min−1) fall within a narrow range, irrespective of the method of calculation. Although the kinetic data most closely fits an Avrami two‐dimensional nucleating model, the data can be just as easily described by a first‐o