Soil-borne plant diseases significantly threaten agricultural sustainability, leading to substantial crop loss. Although chemical pesticides are effective, their environmental and health risks are concerning. Recently, compost has gained attention as a sustainable alternative for managing plant pathogens. Its effectiveness is due to its physical (e.g., particle aggregation and moisture retention), chemical (e.g., pH, electrical conductivity, nutrient balance, and humic substances), and biological properties (e.g., diverse microbial communities). These properties contribute to pathogen suppression through direct mechanisms, involving the release of toxic compounds and competition with compost-introduced microbiota, and indirect mechanisms, including the modulation of plant biochemical pathways, alleviation of oxidative damage, enhancement of defense-related enzymatic activities, and induction of systemic resistance. Overall, this review groups and classify the mechanisms induced by compost, highlighting its potential as a natural substitute to chemical pesticides.