Objective To investigate the rate of nonsuicidal self‐injury (NSSI), to describe sociodemographic and clinical correlates of NSSI, and to examine the association of NSSI with suicidal thoughts and behaviors in a sample of U.S. military personnel and veterans. Method An anonymous online survey was completed by 335 U.S. military personnel and veterans (70.0% male; age mean = 36.67, standard error = 10.59; 82.3% Caucasian, 4.9% African American, 2.8% Asian, 3.7% Native American, 1.2% Pacific Islander, and 7.6% other) enrolled in college classes. Descriptive statistics were calculated, and logistic regression was used to test the associations among NSSI, suicide ideation, suicide planning, and suicide attempts. Results Fourteen percent of the sample reported lifetime NSSI and 3% reported NSSI during the last 12 months. The most common method was cutting (78.7%), with 66% reporting use of 2 or more methods for NSSI. Average age of NSSI onset was 17.55 years. Increased likelihood of NSSI was associated with older age, shorter length of time in service, greater trauma exposure, female gender, Native American racial identity, and combat support deployments. Personnel in the Navy and with a history of combat deployment were significantly less likely to report NSSI. NSSI was significantly associated with suicide ideation, suicide planning, and suicide attempts even when adjusting for covariates. Conclusion The rate of NSSI is comparable to estimates in nonmilitary U.S. samples. NSSI is a significant risk factor for suicidal thoughts and behaviors in this group.