One of the global challenges is micronutrient deficiencies or “hidden hunger”, with selenium deficiency proving to be one of the most important due to its impact on human health. Selenium is a crucial micronutrient that has an essential function in antioxidant defence, regulation of the immune system, and detoxification. However, its deficiency is prevalent, especially in cereal-dependent diets, and it is difficult to manage due to its very small margin between deficiency and toxicity. Biofortification is an efficient and affordable approach that has emerged as a practical solution to combat selenium deficiency by increasing its levels in staple crops like rice, wheat, and maize. This chapter discusses selenium uptake and metabolism in plants, highlighting its beneficial roles in mitigating abiotic stress and heavy metal toxicity. Approaches to selenium biofortification, such as soil and foliar applications and genetic engineering are discussed and critically evaluated. Each approach presents unique advantages and challenges but offers a comprehensive framework for the improvement of selenium content in cereals. Biofortification of selenium has the potential to combat hidden hunger while strengthening sustainable agriculture and food security worldwide by opening a route toward healthy outcomes and resilience in staple crops.