Electromagnetic wave (EMW)-absorbing materials can effectively mitigate the issues arising from the development of electromagnetic technology, such as electromagnetic radiation, communication interference and information leakage. Fiber materials, with the advantages of lightweight, high aspect ratio and pronounced mechanical properties, can enhance the scattering effect and transmission path of EMWs at reduced working thicknesses. Significant research efforts have been dedicated to fiber component modulation and microstructure design toward enhancing the effective absorption bandwidth and the dissipation of EMWs. This review summarizes the recent developments in EMW-absorbing fibers, including their absorption mechanisms, preparation methods, performance optimization and structural design. For inorganic EMW-absorbing fibers, their inherent dielectric properties allow the matrix to absorb EMWs, while doping with additional components further enhances impedance matching. In contrast, organic fibers, which generally lack intrinsic EMW-absorbing capabilities, require hybridization with various organic or inorganic functional materials and structural modifications to optimize EMW-absorbing performance. Finally, emerging trends and ongoing challenges in the development of EMW-absorbing fibers are discussed, with the goal of promoting their practical applications. This review gives new insights into the research of EMW-absorbing fibers and fabrics, which will significantly relieve the imminent concerns regarding electromagnetic radiation.