Small signaling peptides (SSPs), short proteins of fewer than 100 amino acids, serve as pivotal signaling molecules with diverse structural features, post-translational modifications, and functional roles. They regulate various aspects of plant growth and development by modulating specific cellular signaling pathways. Research has shown that many SSPs are essential for mediating responses to environmental stresses. This review presents the structure, characteristics, and classification of plant SSPs and elucidates their roles in resistance signaling pathways through interactions with their specific receptors. We then summarize recent findings on the biological functions and regulatory mechanisms of SSPs in response to both biotic and abiotic stresses. Finally, we discuss the potential applications and future prospects of these peptides in plant protection. This review offers valuable insights for enhancing plant resilience to environmental stress and advancing sustainable agricultural practices, while also providing key references and perspectives to accelerate research on SSPs in plants.