Hydrogen production by thermal decomposition of H2S in the presence of oxygen has been investigated at different operating conditions. It was studied the influence of the main operating parameters like temperature, O2/H2S ratio and residence time on H2S conversion, H2 yield and SO2 selectivity. Experimental results allowed to identify the best values of operating parameters able to assure a high H2S conversion and a good hydrogen yield, minimizing the SO2 selectivity. A kinetic model was developed through the identification of the main reactions that occur in the system. The accuracy of the model was tested under different experimental conditions to evidence the predictive capability of the model. A very good agreement between the mathematical model calculations and the experimental data by varying the feeding molar ratio (O2/H2S) was achieved. •The thermal decomposition of H2S in presence of oxygen has been investigated.•The effect of the temperature, O2/H2S ratio and residence time was studied.•Highest hydrogen production at 1100 °C with O2/H2S ratio = 0.2.•Mathematical modelling through the identification of the main reactions.•A good agreement between the model and the experimental data was achieved.