Peptide vaccines offer promise in cancer immunotherapy, leveraging specificity, safety, and the potential for targeted immune responses against tumors. By incorporating multiple epitopes, they enhance immune recognition and can be customized based on individual patient profiles. This chapter explores peptide vaccines, emphasizing adjuvants that enhance efficacy while balancing safety. Traditional adjuvants like alum and oil-in-water emulsions promote immune cell activation, while toll-like receptor agonists stimulate innate immunity. Strategies to improve efficacy include combining peptide vaccines with other agents and overcoming challenges like low immunogenicity. Future research should refine adjuvant formulations and explore combination therapies to maximize the effectiveness of peptide vaccines against cancer.