The extensive utilization of plastics in modern human society has resulted in severe environmental pollution caused by microplastics (MP/MPs). The escalating consumption of plastics has led to pervasive presence of microplastics in aquatic environments, which not only carry toxic organic matter, transport toxic chemicals, but also spread through the food chain, seriously threatening marine life and human health. Therefore, various advanced strategies have been developed for separating and degrading MPs from water. Using magnetic materials and their nanostructures for targeting, adsorbing, transporting, and degrading MPs is a promising strategy. However, a comprehensive review of MP remediation using magnetic materials and their nanostructures is currently lacking. The present work aims to fill in the gap by providing a critical review of the recent advances in MP removal/degradation using magnetic materials. The primary focus is to compare and analyze MP’s removal efficiencies of different magnetic materials, including iron/ferrite nanoparticles, magnetic nanocomposites, and micromotors, aiming to unravel the underlying roles of magnetic materials in different types of MP degradation and present the general strategies for designing them to achieve optimal performance. Finally, the review outlines the forthcoming challenges and perspectives in the development of magnetic nanomaterials for MP remediation.