Cadaverine (Cad), a diamine belonging to the polyamine (PA) family, has emerged as a crucial molecule in modulating plant responses to environmental stressors. It is biosynthesized through the activity of lysine-by-lysine decarboxylase (LDC) and is involved in various physiological processes, including cell division, membrane stabilization, and reactive oxygen species scavenging. Recent studies highlight cadaverine’s role in enhancing tolerance to both abiotic and biotic factors, often through cross talk with signaling molecules like abscisic acid, salicylic acid, and jasmonic acid. This chapter discusses the biosynthetic pathways and metabolic regulation of cadaverine in plants and explores its involvement in stress signaling networks. We also discuss the transport and accumulation dynamics of cadaverine, its influence on ion homeostasis, and its interaction with antioxidant systems under stress conditions. The potential of cadaverine as a biostimulant in agricultural practices is examined, along with future directions in genetic engineering and breeding strategies aimed at optimizing cadaverine levels to improve crop resilience.