The reaction of aqueous iron(VI) (Fe^VIO₄²⁻, Fe(VI)) with ethylenediaminetetraacetic acid (EDTA) was studied kinetically as a function of pH (1.98–12.40) and temperature (15–45 °C) using a stopped flow kinetic technique. The rate law for the reaction of Fe(VI) with EDTA was found to be first-order with respect to each reactant over the entire studied pH range. The observed rate constants, k, decrease with an increase in pH, varying from 4.19 × 10⁴ to 8.60 × 10⁻² M⁻¹ s⁻¹ over the pH range. The speciation of Fe(VI) (H₃FeO₄⁺, H₂FeO₄, HFeO₄⁻, and FeO₄²⁻) and EDTA (H₄Y, H₃Y⁻, H₂Y²⁻, HY³⁻, and Y⁴⁻, Y = EDTA) species was used to explain the pH dependence of the k values. From the temperature effect on k at pH 5.4, 7.1, and 9.2, activation parameters, ΔS^‡ and ΔH^‡, were obtained for the reactions of Fe(VI) with EDTA. The values of ΔS^‡ for the reactions were found to be negative, implying a highly ordered transition state in the reaction. The ΔH^‡ for the reaction at pH 7.1 and 9.2 showed similar values within experimental error. Using the observed enthalpy parameters and the enthalpy of deprotonation of HFeO₄⁻ and EDTA species (HEDTA³⁻ and H₂EDTA²⁻), the enthalpy of deprotonation of H₂FeO₄ (ΔH⁰_H2FeO4) was determined as 5.7 ± 3.0 kJ mol⁻¹. The reactivity of Fe(VI) with aminopolycarboxylates (APCs) was also studied in alkaline medium. The order of reactivity was determined as primary > secondary > tertiary, which suggests that Fe^VIO₄²⁻ attacks at the nitrogen atom sites of APCs.