Supercapacitors (SCs) are a promising energy storage solution in the face of increasing demand for electrification. Development of efficient and low-cost electrode materials is critical to advancing high-performance SCs. Iron-rich materials have shown potential due to their flexible nanostructures, various nanocomposites, and cost-effective synthesis routes. This review summarizes recent progress on iron oxides/hydroxides, iron-based heteroatom compounds, and iron-based bimetallic compounds, focusing on their morphologies and potential applications in SCs. The conventional working principles and unique mechanisms of iron-based SCs are discussed, along with various techniques for enhancing their performance, such as defect engineering, construction of nanocomposite electrode structures, and electrolytes with Fe3+ and Fe2+ as redox agents. Finally, the review highlights effective strategies and future challenges of iron-based electrode materials for high-performance SCs. This comprehensive summary will be valuable for researchers and engineers interested in advancing the development of high-performance SCs using iron-based electrode materials.