OBJECTIVE: Cognitive behavioural therapy (CBT) is increasingly used to manage Disorders of Gut-Brain Interaction (DGBIs). This systematic review aimed to review the evidence for the effectiveness of CBT-based interventions for patients with gastroduodenal DGBIs. METHODS: Medline, Embase, PubMed, Cochrane Central, and Scopus were searched in July 2022. Studies were included if they investigated the effects of a CBT-based intervention on gastrointestinal symptoms and/or psychological outcomes pre- and post-intervention in patients with gastroduodenal DGBIs. Case studies, studies not in English, and studies with patients under 18 years were excluded. Results were synthesised narratively, and standardised effect sizes were calculated where possible. RESULTS: Nine studies (seven RCTs and two pre/post studies) were identified, with data reported in 10 articles (total N = 602). The studies investigated patients with functional dyspepsia (n = 7), rumination syndrome (n = 1), and supragastric belching (n = 1). The studies had heterogeneous interventions, methodologies, and outcomes, precluding meta-analysis, as well as a moderate-high risk of bias and high drop-outs rates. Findings demonstrated decreased gastrointestinal symptoms and improved anxiety, depression, and quality of life, from pre- to post-intervention, with medium to large effect sizes for symptoms and small to large effect sizes for psychological outcomes. Efficacy was maintained at follow-up, up to one year later. CONCLUSIONS: This review suggests promising evidence that CBT effectively improves gastrointestinal symptoms and psychological outcomes in patients with gastroduodenal DGBIs. However, heterogeneity, risk of bias, and lack of statistical reporting were noted, indicating the need for more robust research and standardisation.