Pediatric gastroenterological disorders are frequently encountered by the practicing pediatric psychologist and can be challenging to treat due to the range of presenting symptoms and potentially high impact on patient’s functioning. In this article, the authors aim to (a) describe the brain–gut axis as a means to increase understanding among pediatric psychologists of the biological mechanisms implicated in pediatric GI disorders and how their interactions with psychological and contextual factors maintain GI symptoms and (b) provide practical ways for pediatric psychologists to incorporate the discussion of biological mechanisms and the brain–gut axis into patient education and psychological interventions. Biological mechanisms of the brain–gut axis including alterations in pain processing, the stress response system, and gut microbiome activity will be reviewed. Psychosocial factors that contribute to or maintain disturbances in the brain–gut axis are discussed with implications for clinical assessment and intervention. The authors assert that a mutual understanding by patients, families, and providers alike of the relevant brain–gut interactions and the biopsychosocial model, in general, will serve as a foundation for successful delivery of and adherence to psychological intervention.