Protonic ceramic fuel cells (PCFCs) are promising eco-energy electrochemical energy conversion systems that can efficiently operate in intermediate (500–700 °C) to low (500 °C) temperature ranges. In this review the most recent advances in materials research for the ceramic components of PCFCs (i.e., electrolyte, cathode, and anode) and their interface engineering are introduced. Recent approaches to improve the protonic of conductivity, and activity and stability of electrolyte and electrode materials are first presented. In addition, new attempts to stabilize/activate electrode/electrolyte interfaces and electrode surfaces are also discussed. Details of the theoretical background behind the electron and ion transfer processes at electrodes are also discussed. Finally, the challenges and perspectives of PCFC development are suggested from the point of view of materials engineering.