A low-FODMAP diet is considered as a potential supportive treatment approach in some gastrointestinal disorders. The aim of this study was to systematically review the literature for randomized controlled trials assessing the efficacy of the low-FODMAP diet on the severity of gastrointestinal symptoms and quality of life in patients with gastrointestinal disorders. This review was conducted in accordance with CASP tool and PRISMA guidelines. A comprehensive search of the PubMed, Scopus, and Web of Science databases resulted in the identification of fourteen randomized controlled trials. Ten studies examined the effect of the low-FODMAP diet in patients with irritable bowel syndrome (IBS), three with inflammatory bowel disease (IBD), and one with symptomatic proton pump inhibitor (PPI) refractory gastroesophageal reflux disease (GERD). All interventions compared the low-FODMAP diet with another diet and lasted from 3 to 12 weeks. Most studies on IBS showed significant improvements in abdominal pain, bloating, and quality of life compared to control diets. In IBD, improvements were mainly observed in functional gastrointestinal symptoms, while no clear benefit was demonstrated in GERD. Heterogeneity in study designs, intervention durations, comparator diets, and outcome measures limited the ability to conduct a meta-analysis. Although a low-FODMAP diet may reduce symptoms in selected individuals, it is not universally necessary. Importantly, the diet's restrictive nature and potential long-term effects-such as nutritional deficiencies and alterations in gut microbiota-highlight the need for clinical supervision by dietitians with expertise in gastrointestinal disorders. Furthermore, in some cases, symptom improvement may be achievable through less restrictive changes, such as improving food hygiene and reducing intake of processed or high-sugar foods. Further high-quality randomized controlled trials with standardized endpoints and longer follow-up are needed to clarify the efficacy and safety of the low-FODMAP diet across various gastrointestinal conditions.