The direct electrolysis of liquid anhydrous ammonia (NH3(l), >99.99% of NH3, free of water and solvent) is demonstrated using a 25 cm2 zero-gap electrolyzer, consisting of a Ru/C anode and a Pt/C cathode, with the two electrodes spatially separated by a cation exchange membrane. This system, supplied by NH3(l) and NH4Br as the supporting electrolyte, continuously produces high-purity and pressurized hydrogen (H2, >99.99%, >5.5 bar) at a temperature of 10 °C and a pressure of 6.2 bar, without requiring H2/N2 separation and compression processes. The direct NH3(l) electrolyzer exhibits a cell potential of 1.1 V at 0.1 A cm−2, presenting a faradaic efficiency of >99.3% for H2 production. The developed system achieves a H2 production rate of >18.8 mol-H2 gcat−1 h−1 at 0.5 A cm−2, which is 4.7-fold higher than the highest H2 production rate reported to date for NH3(g) thermolysis at temperatures of over 500 °C.​