<p>Ammonia is a promising zero-carbon alternative fuel. Direct ammonia fuel cells (DAFCs), as an efficient ammonia-fueled power system, have an extremely high application value in the field of transportation for decarbonization. Metals are essential components for catalysts and electrolytes in DAFCs, with catalysts being critical to their overall performance. Currently, ammonia-fueled solid oxide fuel cells with Ni-based catalysts have reached peak power densities exceeding 1000 mW·cm⁻². In the case of anion exchange membrane fuel cells, platinum-group metal catalysts can achieve a peak power density of 410 mW·cm⁻². Despite these advancements, further development of more efficient, stable, and cost-effective catalysts is necessary to meet the demands for high efficiency and power density in transportation power systems. This review comprehensively summarizes the recent advancements of metal materials in DAFCs, as well as the potential applications of DAFCs in the transportation sector.</p> Graphical Abstract <p></p>