Arbuscular mycorrhizal fungi (AMFs) are vital soil microorganisms that establish symbiotic associations with approximately 80% of terrestrial higher plants, significantly enhancing plant growth, soil fertility, and ecosystem sustainability. Their role as biocontrol agents against soil-borne pathogens has garnered increasing attention, providing an environmentally friendly alternative to synthetic pesticides. AMF-mediated pathogen suppression occurs through multiple mechanisms, including direct competition with pathogens for root colonization sites, modulation of soil physical and chemical properties, and promotion of beneficial rhizosphere microorganisms. Additionally, AMFs enhance plant defense systems by inducing the production of secondary metabolites, regulating phytohormones, and activating defense-related gene expression. This chapter discusses the diverse strategies employed by AMFs to boost plant immunity and suppress agricultural pathogens, including fungi, bacteria, and nematodes. Key aspects include root morphological alterations, AMF-induced systemic resistance, and the regulation of nutrient distribution within the rhizosphere. The potential of AMFs in mitigating disease severity, particularly under low-input or organic farming systems, underscores their significance as cost-effective tools for sustainable agriculture. The synergistic interactions between AMFs and other beneficial rhizosphere organisms further highlight their role in creating a resilient agricultural system. By unraveling the molecular pathways and ecological functions of AMFs, this chapter aims to enhance their application in crop protection and contribute to sustainable farming practices.