Traumatic brain injury (TBI) is a disease type with high mortality and disability rates, and effective treatments to prevent long-term neurological dysfunction remain lacking. Recent animal studies have shown that the ketogenic diet (KD) can exert neuroprotective effects and promote neurological recovery by regulating energy metabolism, enhancing mitochondrial function, and alleviating neuroinflammation, thereby providing a novel strategic direction for the treatment of TBI. This review explores the physiological and metabolic effects of KD, its potential neuroprotective mechanisms in TBI, and its clinical applications, aiming to provide a theoretical basis for further basic research and clinical translation of KD in TBI.