Trehalose, a naturally occurring disaccharide, has been extensively studied for its multifunctional roles in maintaining cellular homeostasis and protecting cells from various stress factors. This review highlights the diverse protective functions of trehalose, including its ability to act as an osmoprotectant, chemical chaperone, free radical scavenger, carbon source, virulence factor, and metabolic regulator. Trehalose's unique properties, such as high hydrophilicity and chemical stability, make it an effective osmolyte that can protect cells from desiccation, oxidative stress, and other environmental challenges. The accumulation of trehalose in cells is regulated by a balance between synthesis and degradation pathways, which are influenced by environmental conditions and cellular needs. Additionally, trehalose has been found to play a regulatory role in glucose metabolism and plant development, as well as in the pathogenicity of bacteria and fungi. Its neuroprotective effects have also been documented, particularly in the context of neurodegenerative diseases. Trehalose's potential therapeutic applications are discussed, including its use in treating neurodegenerative disorders, diabetes, and other pathological conditions. The review concludes by emphasizing the ongoing research into the mechanisms and therapeutic potential of trehalose, highlighting its significance in both basic science and clinical applications.Trehalose, a naturally occurring disaccharide, has been extensively studied for its multifunctional roles in maintaining cellular homeostasis and protecting cells from various stress factors. This review highlights the diverse protective functions of trehalose, including its ability to act as an osmoprotectant, chemical chaperone, free radical scavenger, carbon source, virulence factor, and metabolic regulator. Trehalose's unique properties, such as high hydrophilicity and chemical stability, make it an effective osmolyte that can protect cells from desiccation, oxidative stress, and other environmental challenges. The accumulation of trehalose in cells is regulated by a balance between synthesis and degradation pathways, which are influenced by environmental conditions and cellular needs. Additionally, trehalose has been found to play a regulatory role in glucose metabolism and plant development, as well as in the pathogenicity of bacteria and fungi. Its neuroprotective effects have also been documented, particularly in the context of neurodegenerative diseases. Trehalose's potential therapeutic applications are discussed, including its use in treating neurodegenerative disorders, diabetes, and other pathological conditions. The review concludes by emphasizing the ongoing research into the mechanisms and therapeutic potential of trehalose, highlighting its significance in both basic science and clinical applications.