Objective To systematically evaluate the risk factors for malnutrition in patients with traumatic brain injury (TBI) and to provide evidence-based references for early risk screening and nursing interventions. Methods A systematic literature search was conducted across domestic and international databases for studies published between January 1, 2000 and July 31, 2025 reporting the risk factors for malnutrition in TBI patients.Eligible studies that met the inclusion criteria were subjected to methodological quality assessment and data extraction.Meta-analysis was conducted using Stata 17.0 and RevMan 5.4. Results A total of 12 studies involving 2,125 TBI patients were included.Meta-analysis indicated that advanced age, low Glasgow Coma Scale score, dysphagia, pulmonary infection, urinary tract infection, mechanical ventilation, low total protein, low albumin and low hemoglobin were risk factors for malnutrition in TBI patients （all P＜ 0.05）. Conclusion Malnutrition in TBI patients is affected by various factors.Medical staff should prioritize identification of high-risk individuals early on and implement personalized nutritional support to reduce the incidence of malnutrition and improve patient outcomes.