Stimuli-responsive peptides have emerged as promising smart materials for biomedical applications due to their multifunctionality, unique self-assembly ability, high biocompatibility, and ease of customization. Stimuli-responsive peptides have been widely used in tissue engineering, regenerative medicine, diagnostics, and drug delivery systems and could achieve controlled drug release, targeted delivery, and non-invasive operations. The synergistic effects of multiple stimuli-responsive domains within a single peptide system, the design of peptide sequences, and the physicochemical properties for specific functions, as well as the development of rationally designed stimuli-responsive peptide materials are all the hot topics in this promising research field. This chapter focuses on the design, synthesis, and applications of various types of stimuli-responsive peptides, including the thermo-responsive, pH-responsive, light-responsive, metal-ion-responsive, and enzyme-responsive ones, each of them have exhibited unique responses to specific environmental triggers.