The aquaculture industry is rapidly expanding day by day to meet the nutritional demands of the world population. As a crucial global industry, aquaculture faces the challenge of sustainable growth and resource optimization. To address these issues, functional feed additives have emerged as an innovative solution to enhance aquaculture’s health, nutrition, and sustainability. This chapter offers an overview of functional feed additives in aquaculture, emphasizing their potential benefits and applications. These additives encompass a variety of bioactive compounds such as probiotics, prebiotics, enzymes, phytogenics, vitamins, etc., carefully integrated into aquafeed to improve the well-being of cultured species, resulting in improved growth, disease resistance, and overall productivity. Functional feed additives enhance feed digestibility, boost immunity, and reduce the reliance on antibiotics, contributing to more efficient and environmentally friendly aquaculture. Adopting functional feed additives aligns with the industry’s broader sustainability goals, promising improved aquaculture performance and environmental responsibility. In summary, incorporating functional feed additives represents a significant stride towards sustainable and efficient aquaculture practices, offering a comprehensive approach to enhance the health, nutrition, and environmental stewardship of aquatic animals, shaping the future of aquaculture and improving food security.