Folic acid deficiency, a critical global health issue, significantly impacts various population groups, particularly pregnant women and individuals with dietary restrictions. This chapter provides an in-depth analysis of folic acid deficiency, focusing on its epidemiology, causes, and clinical manifestations, including megaloblastic anemia and developmental complications. It underscores the crucial role of folic acid in human physiology, notably in DNA synthesis and repair. Additionally, the chapter discusses the complex nature of folic acid deficiency, which encompasses dietary inadequacies, malabsorption issues, and medication interactions, and confronts the challenges in diagnosis. Management strategies such as dietary modifications, supplementation, and public health policies, including fortification, are thoroughly examined. In conclusion, a multifaceted approach is vital for mitigating the impact of folic acid deficiency and enhancing health outcomes.