Background <p>The increasing demand for sustainable and environmentally responsible agricultural practices has accelerated the search for alternatives to chemical fertilizers. Microbial biofertilizers, particularly plant growth-promoting rhizobacteria (PGPR), offer a promising strategy to enhance crop productivity while maintaining soil health. Among these, <i>Bacillus</i> species have gained significant attention due to their ecological versatility and functional diversity.</p> Main text <p>This review provides a comprehensive evaluation of the biofertilization potential of <i>Bacillus</i> spp. in sustainable agriculture. Prominent species such as <i>Bacillus subtilis</i>, <i>B. megaterium</i>, and <i>B. amyloliquefaciens</i> contribute to improved nutrient acquisition through nitrogen fixation, phosphate solubilization, and potassium mobilization. In addition, <i>Bacillus</i> spp. produce phytohormones, siderophores, and volatile organic compounds that stimulate plant growth and enhance tolerance to biotic and abiotic stresses. Their endospore-forming ability ensures high survival, prolonged shelf life, and reliable performance under diverse field conditions, supporting their commercial application as biofertilizers. This review also discusses interactions between <i>Bacillus</i> spp. and native soil microbiota, their influence on rhizosphere dynamics, and their role in improving soil fertility and crop productivity. However, inconsistent field performance, formulation challenges, and regulatory constraints remain key barriers to large-scale adoption.</p> Conclusion <p>Recent advances in genomics, strain improvement, and formulation technologies present new opportunities to enhance the efficacy of <i>Bacillus</i>-based biofertilizers. Integrative approaches combining microbiology, agronomy, and policy frameworks are essential to realize their full potential in sustainable agricultural systems and global food security.</p>