Scientists have uncovered compelling evidence highlighting the critical role of the microbiota-gut-brain axis in regulating sleep and contributing to sleep disorders. A recent comprehensive review published inBrain Medicinesynthesized findings on how gut microbiota composition and function intersect with sleep disturbances, offering new insights into mechanisms, biomarkers, and potential microbiome-targeted interventions. Sleep, essential for physical and mental well-being, is influenced not only by brain circuits but also by the trillions of microbes residing in the gastrointestinal tract. These microbes communicate with the brain through metabolic, neural, and immune pathways, comprising a bidirectional network known as the microbiota-gut-brain axis. Disruptions in this axis are consistently associated with diverse sleep disorders—including insomnia, obstructive sleep apnea (OSA), and circadian rhythm disturbances—as well as neuropsychiatric conditions marked by sleep problems. The review highlights convergent alterations in gut microbial diversity and metabolite profiles across multiple sleep disorders. For example, chronic insomnia is linked to reduced microbial alpha-diversity and shifts in bile acid metabolism, with elevated primary bile acids and decreased secondary bile acids correlating with cardiometabolic risks. OSA studies indicate decreased abundance of beneficial short-chain fatty acid (SCFA)-producing bacteria like Ruminococcaceae and mixed changes in Faecalibacterium, aligned with disease severity. Communications along the microbiota-gut-brain axis involve numerous pathways: microbial metabolites such as SCFAs, gamma-aminobutyric acid (GABA), serotonin, and melatonin influence sleep regulation. Neural circuits, including vagal pathways and the hypothalamic–pituitary–adrenal (HPA) axis, mediate signals between the gut and sleep centers in the brain, influencing sleep-wake cycles and responses to stress. Emerging interventions aiming to modulate gut microbiota—such as prebiotics, probiotics, synbiotics, and fecal microbiota transplantation—have shown promising improvements in sleep quality metrics in preliminary trials, including insomnia and autism spectrum disorder with sleep problems. However, larger, controlled studies are needed to confirm efficacy and develop standardized treatment protocols. For patients and families, practical strategies like fiber-rich diets, consistent sleep schedules, and supporting gut health may complement medical treatments for sleep disorders. These findings open new avenues for holistic, microbiome-informed therapies that address underlying biological disruptions common to sleep and neuropsychiatric disorders. REFERENCE: Wang, Z., Wu, T., Li, J., Lu, T., Yu, Y., Guan, Z., Yuan, G., Lv, Z., Shan, Y., Yan, W., Liu, X., Vitiello, M. V., Yin, Q., Sun, J., & Lu, L. (2025). Brain-gut-microbiota interactions in sleep disorders. Brain Medicine, 1–22. DOI: 10.61373/bm025i.0128