<p>Ammonia is regarded as “Hydrogen 2.0” and is an ideal zero-carbon energy source. Electrocatalysis technology enables the synthesis of ammonia at room temperature and pressure. Iron-based catalysts exhibit great potential in electrocatalytic ammonia synthesis because of the unfilled d-orbital of iron sites, which are beneficial for the adsorption and activation of reactive species. This review unveils cutting-edge developments of iron-based catalysts in electrocatalytic ammonia synthesis. Firstly, the fundamental principle of electrocatalytic ammonia synthesis is introduced. The nanostructure-catalytic activity relationship, the electronic structure-catalytic activity relationship, and the influence of electrolyte properties on catalytic performance are also analyzed to work out the key parameters for designing efficient iron-based catalysts and electrodes. Lastly, the challenges and development prospects of iron-based catalysts for electrocatalytic ammonia synthesis are highlighted to guide the development of low-cost and large-scale sustainable electrocatalysts. </p>