BACKGROUND: Within the framework of gut-brain interactions, the ketogenic diet (KD), a high-fat, low-carbohydrate, and moderate-protein dietary intervention, has gained attention for its potential in psychiatric care. Renowned for its efficacy in managing obesity, KD has demonstrated effectiveness in facilitating weight loss and inducing favorable metabolic changes in the short term. With its established benefits in neurological disorders, KD is now being investigated as a potential therapeutic avenue for individuals with psychiatric conditions. OBJECTIVE: This scoping review aims to summarize the latest studies on this topic, consider clinical implications, and suggest future research directions. METHODS: Records were systematically (PRISMA-ScR guidelines) identified through PubMed, Scopus, and EBSCOhost searches. RESULTS: A total of 58 studies were initially identified, with 13 meeting the eligibility criteria. While clinical trials remain limited, emerging evidence from case reports, case series, and pilot studies highlights the potential of a KD in reducing symptoms across psychiatric conditions, including mood disorders, psychotic disorders, alcohol use, and eating disorders. A KD shows potential in reducing cravings in eating and alcohol use disorders by stabilizing brain metabolism and modulating addictive behaviors, while its neuroprotective and anti-inflammatory effects may contribute to symptom improvement in mood and psychotic disorders. CONCLUSIONS: Implementing a KD in patients with mental disorders seems to be a feasible and well-tolerated approach, resulting in psychiatric symptom reduction and improvements in metabolic health. Most interestingly, research suggests that KD can also be safely implemented in the care of patients with addictive-like eating disorders.