Objective: Traumatic brain injury (TBI) and persistent postconcussion symptoms (PPCS) are associated with increased substance use among veterans. Each factor is independently associated with the perpetration of violence; however, little is known about the associations TBI and PPCS have with violence among substance users. This study examined the distinct associations probable TBI and PPCS have with partner aggression (PA) and nonpartner aggression (NPA) in substance-using veterans. Method: Present sample included 810 veterans (6.7% women; Mage = 48.2, SD = 13.3) who completed self-report measures assessing sociodemographic characteristics, past month binge drinking and cocaine use, probable TBI, PPCS, probable posttraumatic stress disorder (PTSD), and chronic pain. Aggression measures included psychological, physical, and injury-related PA and NPA. Results: Bivariate analyses revealed age, probable PTSD, and PPCS were associated with most forms of PA and NPA, whereas race, cocaine use, pain, and TBI severity were mostly associated with NPA. Multivariate negative binomial regression analyses adjusting for other identified risk factors (e.g., age, probable PTSD, and chronic pain) revealed PPCS, but not TBI, was associated with most forms of PA and NPA. Conclusions: Findings highlight the importance of PPCS as a risk factor for PA and NPA in substance-using veterans and have important implications concerning the screening of violence risk.