In sustainable agriculture, biological control is an eco-friendly and effective means of mitigating pests and their impacts using biological control agents (BCAs). Biological control has been known since ancient times; however, we understand its importance in today’s world. Biocontrol agents (BCAs) are naturally beneficial organisms or gene products that are used to reduce the impact of undesirable organisms on plants. These agents exert direct or indirect effects on parasitism, antibiosis, and competition for pests. Predators, parasitoids, pathogens, and competitors are examples of biocontrol agents, each with a distinct role in pest management. The diversity and effectiveness of biocontrol agents are influenced by multiple factors such as management practices, environmental conditions, habitat complexity, and community interactions. Understanding these dynamics is essential for optimizing biocontrol strategies and reducing nontarget impacts. As sustainable agriculture becomes increasingly essential, biocontrol becomes a potential and ecologically beneficial strategy that necessitates continual study and innovation. This chapter aims to provide an overview of the history, diversity, and community dynamics of biocontrol agents, highlighting their importance and potential for sustainable pest management.