Phytomelatonin is a powerful biomolecule that plays a key role in regulating various physiological and biochemical processes in plants. It is present in various plant tissues, such as roots, leaves, and seeds, and helps in plant growth regulation, seed germination, root development, flowering, and fruit development. The multifaceted melatonin has a recent interest for its role in plant growth and development and protection from biotic and abiotic stresses. Due to the elevated harmful effects of pesticide and global climate change, melatonin has led to great interest in plant applications. The omics advancements have unraveled the most complex and in-depth molecular processes behind melatonin-induced changes in plants. The role of melatonin in maintaining cellular homeostasis via post translational changes and signaling cascades is well studied with the proteomic approach. Melatonin increases plant resistance to biotic and abiotic stressors by regulating gene expression, protein function, and metabolic pathways. Experimental evidence for its multifunction, plant growth, development, and stress adaptation using various techniques is needed for its field usage agriculture, horticulture, and forestry ecosystems. The recent experimental evidence and discovery of melatonin effects on plant growth and development, regulation of phytohormone, and biotic and abiotic stress adaptation have been summarized in this chapter, and also avenues for future work. Gaining insight into the recent advancements in phytomelatonin research will pave the way for sustainable agricultural practices and improved global food security.