Nonsuicidal self-injury (NSSI) is a robust predictor of suicidal thoughts and behaviors; however, while there are typically only small differences observed in the prevalence of NSSI between men and women, this condition has been largely overlooked and underestimated among men. Assessing NSSI methods more common in men may address misidentification as well as allow for more precise NSSI prevalence estimates. Survey data from a national sample of Gulf War I-Era veterans (N = 1063) was used to estimate the prevalence of NSSI and compare prevalence of NSSI methods between men and women veterans. Demographic and clinical correlates of NSSI engagement were also examined. The national lifetime prevalence rate of NSSI among Gulf War I-Era veterans was 22.40%, whereas the past year prevalence rate was 8.10%. In both men and women, wall/object punching was the most common NSSI method endorsed across the lifetime. Men had slightly higher overall NSSI prevalence rates compared with women. This study highlights the need to systematically assess NSSI, particularly among veterans, to better identify, and consequently treat, NSSI in men. This is the first available prevalence estimate of NSSI to include the assessment of wall/object punching in a national sample of adult veterans.