Agri-food waste is one of the most abundant biomass resources globally, generated through ongoing agricultural activities and food industry operations. Around 30 % of food produced for human consumption is lost during production and processing, contributing to an estimated 150 billion metric tons of waste annually—an amount projected to grow by 7.5 % each year. Conventional disposal methods such as landfilling, and incineration result in significant environmental harm and economic loss. However, agri-food waste contains valuable organic compounds that can be repurposed into value-added products, supporting the transition to a zero-waste circular economy. This review compiles recent advancements in the generation, categorization, and valorization of agri-food waste, highlighting its potential in biotechnology for producing antibiotics, fermented foods, nutraceuticals, and industrial materials. By aligning with UN Sustainable Development Goals (SDGs) 11, 12, and 13, the review underscores the need for increased research, technological innovation, and public awareness to foster sustainable waste management practices.