The invention relates to a process for gas phase electrochemical oxidation of H2S to sulfur and water or steam using an electrolysis cell having an anode chamber on one side of a solid proton conducting membrane and a cathode chamber on the other side of the membrane. The process comprises the steps of passing H2S-containing gas through the anode chamber to contact a catalytic anode, where it reacts to produce elemental sulfur, protons and electrons. The protons pass through the membrane from the anode chamber to the cathode chamber. An oxygen-containing gas is passed through the cathode chamber to contact the catalytic cathode, where it reacts with protons and electrons to produce water or steam. During the process, both the anode chamber and cathode chamber are maintained at a temperature of at least 120° C. and an elevated pressure sufficient to keep the membrane moist. Sulfur is obtained in liquid or vapor form and is removed from the anode chamber while water or steam is removed from the cathode chamber. An electric current can be withdrawn from the anode and cathode. The cell can also be operated in the electrolysis mode to produce sulfur and hydrogen.