The rising demand for sustainable agriculture necessitates alternative methods to using chemical pesticides for controlling plant pathogens. Biocontrol involves the use of natural antagonists, such as bacteria, as an alternative to synthetic chemical pesticides, which can be harmful to human health and the environment. This review discusses the potential of Bacillus, Streptomyces, Pseudomonas and Serratia as biocontrol agents (BCAs) against various plant pathogens. These bacteria suppress pathogen growth via various mechanisms, such as antibiosis, nutrient and space competition and systemic resistance, and significantly contribute to plant growth. We provide an overview of the secondary metabolites, plant interactions and microbiota interactions of these bacteria. BCAs offer a promising and sustainable solution to plant pathogens and help maintain the one-health principle.