Melatonin receptors (MT Receptors) belong to the G protein-coupled receptor family, primarily including the MT1 and MT2 subtypes. These receptors are mainly distributed in the brain, retina, and other tissues, and they participate in regulating circadian rhythms, sleep, and seasonal physiological changes by activating the cAMP and IP3 signaling pathways. The structural feature of MT receptors is seven transmembrane helical structures. Their tissue-specific expression in different tissues is associated with various physiological and pathological processes, including mood disorders, sleep disorders, and metabolic disorders. Mutations or dysregulation in the MT receptor genes may lead to disruptions in circadian rhythms and related diseases.