The authors present here the decomposition of un-irradiated (pristine) as well as of gamma (γ) and electron beam (EB) irradiated samples of europium (III) acetate hydrate (EuAc.xH₂O) in the temperature range of 25-900  in the air atmosphere. Two absorbed doses of 10³ (γ-ray) and 10² kGy (EB) were examined. The profiles of the TG curves of the dehydration process display noticeable changes in induction periods and mass loss percentages by exposure to irradiation. The kinetics of the dehydration process were analyzed using both model-fitting and model-free approaches. The dehydration process was controlled by the phase boundary model (R₂). The −α plots indicate that the dehydration is not a complex process and follows one reaction mechanism. Powder X-ray diffraction displayed that europium acetate hydrate crystallizes in a monoclinic system (SG P2/m), and no phase transformation was detected by two sources of irradiation up to 10³ (γ-ray) and 10² kGy (EB). Thermodynamic parameters of the dehydration process were calculated and assessed. A predicted thermogram (TG) of the isothermal dehydration of EuAc.xH₂O was constructed from non-isothermal data and used to determine the reaction model and the kinetic parameters of the dehydration process.