Summary The effect of hydrogen sulfide (H2S) on dry reforming of biogas for syngas production was studied both experimentally and theoretically. In the experimental work, the H2S effect on Ni‐based catalyst activity was examined for reaction temperatures ranging from 600°C to 800°C. It was found that the presence of H2S deactivated the Ni‐based catalysts significantly because of sulfur poisoning. Although bimetallic Pt‐Ni catalyst has better performance compared with monometallic Ni catalyst, deactivation was still found. The time‐on‐stream measured data also indicated that sulfur‐poisoned catalyst can be regenerated at high reaction temperatures. In the theoretical work, a thermodynamic equilibrium model was used to analyze the H2S removal effect in dry reforming of H2S‐contained biogas. Calcium oxide (CaO) and calcium carbonate (CaCO3) were used as the H2S sorbent. The results indicated that H2S removal depends on the initial H2S concentration and reaction temperature for both sorbents. Although CO2 was also removed by CaO, the results from equilibrium analysis indicated that the dry reforming reaction in the presence of CaO was feasible similar to the sorption enhanced water‐gas shift and steam‐methane reforming reactions. The simulation results also indicated that CaO was a more preferable H2S sorbent than CaCO3 because syngas with an H2/CO ratio closer to 2 can be produced and requires lower heat duty. For H2S‐contained dry reforming of biogas case, CH4 and CO2 conversions decrease as the testing time increases for each reaction temperature. For each reaction temperature, unstable data were also obtained indicating that catalyst suffers from sulfur poisoning and its activity decays significantly as time proceeds. However, at the temperature of 800°C, CH4 and CO2 conversions were higher than those at 750°C. This indicates that high‐temperature operation can significantly mitigate sulfur adsorption, and hence, the saturation sulfur coverages are lower compared with low‐temperature operation.