[en] Highlights: • The flux-weighted average cross sections of ¹²⁷I(γ,xn)^126,124,123I reactions were experimentally determined. • The present result indicates the role of excitation energy and GDR effect. • The production cross-sections of radioactive iodine isotopes are important for the useful medical purpose. - Abstract: The flux-weighted average cross sections of ¹²⁷I(γ,xn)^126,124,123I reactions were experimentally determined with the bremsstrahlung end-point energies of 50 and 70 MeV by activation and off-line γ-ray spectrometric technique, using the 100 MeV electron linac at the Pohang Accelerator Laboratory, Korea. The ¹²⁷I(γ,xn)^126−121I reaction cross sections as a function of photon energy were theoretically calculated using the TALYS 1.8 code. The flux-weighted average cross sections of ¹²⁷I(γ, xn)^126,124,123I reactions as a function of bremsstrahlung end-point energies were also obtained from the literature and TALYS data based on mono-energetic photons and are found to be in close agreement with the present data. The experimental and theoretical ¹²⁷I(γ, xn)^126−121I reaction cross-sections increase with bremsstrahlung energy, which indicates the role of excitation energy. After a certain energy, the individual ¹²⁷I(γ, xn)^126−121I reaction cross sections decrease with increase of bremsstrahlung energy due to opening of other reactions, which indicates sharing of energy in different reaction channels. The radioactive iodine isotopes production cross-sections are important for the useful medical purpose.