INTRODUCTION: Traumatic brain injury (TBI) often leads to disorders of consciousness (DOC) or persistent vegetative state (PVS), characterized by impaired arousal and awareness. Non-invasive brain stimulation (NIBS) techniques have shown promise in modulating cortical excitability and potentially enhancing arousal and alertness in these patients. This systematic review aims to synthesize existing literature on the effects of NIBS on arousal and alertness among TBI patients with DOC or PVS. METHODS: A systematic search was conducted across multiple databases for studies investigating the use of NIBS techniques such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) in TBI patients with DOC or PVS. Studies were included if they assessed changes in arousal or alertness following NIBS intervention. Data extraction and quality assessment were performed using predefined criteria. RESULTS: A total of 11 studies with 475 patients (mean age 46.21 ± 12.31 years) met the inclusion criteria and were included in the review. The majority of studies utilized TMS or tDCS as the NIBS modality. Findings suggest that NIBS may lead to improvements in arousal and alertness among TBI patients with DOC or PVS. However, the magnitude and duration of these effects varied across studies. CONCLUSION: Non-invasive brain stimulation shows promise as a potential intervention for enhancing arousal and alertness in TBI patients with DOC or PVS. Further well-controlled studies are warranted to elucidate optimal stimulation parameters, long-term effects, and potential synergies with other rehabilitation approaches.