Introduction Little is known regarding long-term mortality outcomes after non-fatal suicide attempts among Veterans Health Administration (VHA) patients, which may inform services delivery and program evaluation. Methods For 4,601,081 Veterans with 2005 VHA encounters, we assessed unadjusted and age-adjusted all-cause and cause-specific mortality through 2017, overall and for Veterans with (N = 8243) versus without (N = 4,592,838) 2005 VHA suicide attempt documentation. Standardized mortality ratios compared mortality rates by suicide attempt status. Multivariable proportional hazards regression models assessed age- and gender-adjusted mortality risk. Results Among Veteran VHA users with non-fatal suicide attempt diagnoses, 1.6% died of suicide, 4.6% of non-suicide external causes, and 30.7% of any cause. In age- and gender-adjusted analyses, Veterans who attempted suicide had increased suicide (hazard ratio [HR] = 4.52, 95% confidence interval [CI] = 3.82–5.36), non-suicide external cause (HR = 3.75, 95% CI = 3.38–4.17), and all-cause (separate due to non-proportional hazards: 2006, HR = 2.05, 95% CI = 1.81–2.31; 2007–2017, HR = 1.72, 95% CI = 1.65–1.80) mortality through 2017. Conclusion Over 12 years, Veteran VHA patients with non-fatal suicide attempt diagnoses had increased risk of suicide, non-suicide external cause, and all-cause mortality. Over 98% of Veteran VHA users who had a diagnosed non-fatal attempt did not die by suicide, highlighting additional program evaluation outcomes and opportunities to support physical and mental health.