Iron(III) complexes of o-vanillin oxime have been synthesized and characterized by different physicochemical techniques. The complexes containing thiocyanate, iodide and sulphate ionshave been subjected to non-isothermal decomposition studies in N2 using TGand DTG techniques. The kinetic parameters for both stages of decomposition of these complexes were evaluated by weighted least-squares method using the general approach as well as the Coats–Redfern and Horowitz–Metzger equations. The results indicate that the values of kinetic parameters obtained by these three different approaches agree well.