Iron, one of the essential micronutrients, is needed for electron transport and metabolic processes in almost all living organisms. The ferric form (Fe3+) of iron is insoluble in nature and inaccessible at physiological pH (7.35–7.40). Under iron-limited conditions, metal-chelating agents such as siderophores are synthesized by many bacteria and a few fungi. Siderophores have a high affinity for iron or other metals. In recent years, siderophores have been considered due to their potential applications in different aspects. Siderophores have applications in microbial ecology to enhance the growth of several unculturable microorganisms and can alter the microbial communities. In agriculture, siderophores are used as plant growth promoters by enhancing the Fe uptake by plants and as potential biocontrol agents against phytopathogens. Therefore, they are suitable alternatives for chemical pesticides. Also, siderophores can be applied in the bioremediation of heavy-metal- contaminated samples and as a biosensor. In this article, the different uses of these iron-chelating molecules are highlighted.