Abstract: With continuously evolving wireless communication technologies, the technological revolution marked by advances in artificial intelligence, the Internet of Things, and the metaverse is fundamentally reshaping our society, making it more convenient, intelligent, and information-centric. However, owing to the booming development and popularization of 5G and mankind’s over-reliance on a variety of smart devices, electromagnetic waves have permeated every aspect of people’s lives. This has led to an alarming increase in the density of electromagnetic radiation and electromagnetic pollution. Electromagnetic absorption materials are functional materials that efficiently absorb incident electromagnetic waves and convert microwave energy into Joule heat to process external electromagnetic waves, thereby regulating them. Over the last few decades, electromagnetic wave-absorbing materials have made significant strides and are playing increasingly crucial roles in radiation protection and antiradar detection, owing to their effective attenuation of incident electromagnetic waves. With the vigorous development of nanotechnology, the design of high-performance electromagnetic wave-absorbing materials has relied on the intrinsic properties of single-component media and has focused on the synergistic effect of different components, resulting in rich loss mechanisms. In recent years, carbide-based composites have received increasing attention in the field of electromagnetic absorption. Among the various candidate materials, carbides are typically characterized by chemical stability, low density, tunable dielectric properties, and diverse morphologies/microstructures. Therefore, exploring and designing carbide-based composites is a feasible approach for the development of novel electromagnetic wave-absorbing materials with promising prospects for practical applications. A summary of the status of the development of carbide-based composites as a new generation of electromagnetic wave-absorbing materials would be helpful for understanding and furthering their advancement. In this review, we introduce the electromagnetic loss mechanisms associated with dielectric composites and discuss the recent advances in the use of various types of carbide-based composites as high-performance electromagnetic wave-absorbing materials. These composites include covalent carbides, interstitial carbides, less common carbide-based composites, and multicomponent composites, such as MXene and high-entropy MAX phase carbides. Key information on composition optimization, structural engineering, performance enhancement, and structure–function relationships are discussed. Additionally, the properties of representative composites are compared, and the challenges and prospects associated with the development of carbide-based composites are presented.