Abstract Mental health problems among adolescents have become a major public health concern, with far reaching implications for their physical and psychological development and social functioning. In order to understand the association and potential mechanisms between gut microbiota and mental disorders in adolescents, the review summarizes the characteristics of gut microbiota alterations in adolescents and the evidence linking these alterations to common mental disorders, including depression and anxiety. From the perspective of the microbiota-gut-brain axis, it further discusses the mechanisms through which the gut microbiota may influence emotional disorders, including neurotransmitter regulation, hypothalamic-pituitary-adrenal axis response, and immune and inflammatory responses, to provide a basis for insights into the mechanisms underlying the involvement of the gut microbiota in the development of mental disorders in adolescents.