Ammonia is an important precursor of fertilizers, as well as a potential carbon-free energy carrier. Nowadays, ammonia is synthesized via the Haber–Bosch process, which is a capital- and energy-intensive process with an immense CO₂ footprint. Thus, alternative processes for the sustainable and decentralized ammonia production from N₂ and H₂O using renewable electricity are required. The key challenges for the realization of such processes are the efficient activation of the N₂ bond and selectivity toward NH₃. In this contribution, we report an all-electric method for sustainable ammonia production from nitrogen and water using a plasma-activated proton conducting solid oxide electrolyzer. Hydrogen species produced by water oxidation over the anode are transported through the proton conducting membrane to the cathode where they react with the plasma-activated nitrogen toward ammonia. Ammonia production rates and Faradaic efficiencies up to of 26.8 nmol of NH₃ s^–1 cm^–2 and 88%, respectively, were achieved.