Thermal dechlorination and oxidation process of praseodymium oxychloride, PrOCl, was studied from the view point of reaction kinetics. On the basis of data of thermogravimetry under different oxygen partial pressures at various heating rates, a kinetic analysis was performed using an isoconversional method and a master plot method. The results of the isoconversional method of TG data suggested that the dechlorination and oxidation of PrOCl followed a single step with activation energy of 112.6 ± 3.4 kJ mol −1, and from master plot methods, the reaction was described by a linear-contracting phase boundary reaction.