Arbuscular mycorrhizal fungi (AMF), which act as root symbionts, are widely distributed in the soils of terrestrial ecosystems and significantly influence soil structure dynamics. Glomalin-related soil protein (GRSP), synthesized within the hyphal cell walls, plays a crucial role in forming and stabilizing soil aggregates and contributes to soil carbon sequestration. Due to its recalcitrant nature, glomalin persists in the soil for years, exhibiting a notable capacity to sequester carbon primarily due to its high carbon content and enhanced aggregate stability. Increased aggregate stability in terrestrial ecosystems is positively correlated with the protection of organic carbon, making the soil healthier and more fertile. This chapter highlights the role of GRSP in long-term soil carbon storage, contributing to carbon mitigation in terrestrial ecosystems.