The development of nanoparticle-based vaccines and immunotherapies represents a groundbreaking amelioration in biomedicine, offering novel disease prevention and treatment strategies. This chapter sheds light on a comprehensive overview of the design, mechanisms, and applications of nanofabricates in enhancing the efficacy of vaccines and immunotherapeutic agents. Key topics include the unique properties of nanoparticles that make them suitable for delivering antigens and adjuvants, such as their ability to improve stability, enhance cellular uptake, and facilitate targeted delivery to immune cells. The chapter explores various types of nanoparticulates, including polymeric nanoforms, liposomes, metal nanoparticulates, and virus-like particles, highlighting their role in inducing robust and long-lasting immune responses. The chapter also aims to provide readers an in-depth comprehension of the present situation and potential of vaccines and immunotherapies based on nanoparticles, emphasizing their importance in promoting global health and preventing various diseases.