The long-term use of chemical fertilizers poses significant threats to crop productivity and soil quality. Organic fertilizers, derived from animal manure, human excrement, household waste, and agricultural waste, are effective in improving soil fertility and crop productivity by enhancing soil organic matter (SOM), soil structure, nutrient uptake, water-holding capacity, cation exchange capacity, nutrient use efficiency, and microbial activities. These benefits extend to improved tolerance against abiotic stresses such as drought, salinity, heat, and heavy metal (HM) stresses. Organic fertilizers improve leaf water status, nutrient uptake, nutrient homeostasis, chlorophyll synthesis, osmolyte and hormone production, secondary metabolites, antioxidant activities, and gene expression, thereby enhancing stress tolerance. This review discusses the mechanisms by which organic fertilizers improve soil fertility, crop yield, and nutrient use efficiency, and their effectiveness in mitigating abiotic stresses. The findings highlight the potential of organic fertilizers as a sustainable strategy to enhance soil fertility, crop productivity, and abiotic stress tolerance.The long-term use of chemical fertilizers poses significant threats to crop productivity and soil quality. Organic fertilizers, derived from animal manure, human excrement, household waste, and agricultural waste, are effective in improving soil fertility and crop productivity by enhancing soil organic matter (SOM), soil structure, nutrient uptake, water-holding capacity, cation exchange capacity, nutrient use efficiency, and microbial activities. These benefits extend to improved tolerance against abiotic stresses such as drought, salinity, heat, and heavy metal (HM) stresses. Organic fertilizers improve leaf water status, nutrient uptake, nutrient homeostasis, chlorophyll synthesis, osmolyte and hormone production, secondary metabolites, antioxidant activities, and gene expression, thereby enhancing stress tolerance. This review discusses the mechanisms by which organic fertilizers improve soil fertility, crop yield, and nutrient use efficiency, and their effectiveness in mitigating abiotic stresses. The findings highlight the potential of organic fertilizers as a sustainable strategy to enhance soil fertility, crop productivity, and abiotic stress tolerance.