In the framework of the annual conference series, organized by the European Fuel Cell Forum (www.efcf.com), EFCF2018 covered the 13th European Solid Oxide Fuel Cell & Solid Oxide Electrolyzer Forum chaired by Prof. Ellen Ivers-Tiffée and Dr. André Weber, Karlsruhe Institute of Technology, Germany. Traditionally located in Lucerne, Switzerland, the conference welcomed 440 participants from more than 30 countries representing 6 continents. The conference demonstrated the progress in solid oxide technologies on different levels ranging from fundamental studies to commercial systems. Science and technology of solid oxide materials, devices, systems and products, including their wide range of potential applications were intensively discussed. Besides the classical fuel cell and electrolyzers applications also further solid oxide membrane reactors are presented in gas and energy transformation processes. This special issue comprises papers selected from the 280 presentations given by researcher from universities, research centers and industry at the conference. The papers reflect the growing importance of SOFC and SOE systems. Next to papers in the field of novel materials and fabrication processes, the focus is on design and the resulting performance and lifetime of stacks and systems.