Plant diseases represent a significant challenge to global agriculture and threaten crop productivity and food security. Traditionally, chemical pesticides have been used to combat these diseases; however, their overuse has led to environmental pollution, health risks, and the development of resistant pathogen strains. Biocontrol methods have emerged as sustainable alternatives, utilizing living organisms or their products to suppress plant pathogens and the diseases caused by them. This chapter explores the mechanisms of various biocontrol agents, including microbial antagonists, plant growth-promoting rhizobacteria (PGPR), mycorrhizal fungi, natural compounds, and plant secondary metabolites. Additionally, this chapter provides an overview of various biocontrol agents utilized for effective plant disease management and their successful applications simultaneously, discussing the challenges in adopting biocontrol methods, such as variability in efficacy due to environmental factors and regulatory hurdles, while emphasizing the potential for widespread adoption and its positive impact on sustainable agriculture. This chapter aims to underscore the potential of biocontrol methods to achieve broad-spectrum disease resistance in plants and provides a comprehensive approach to plant disease management that aligns with the global demand for sustainable agricultural practices and contributes to long-term food security.