INTRODUCTION: Returning veterans of the wars in Iraq and Afghanistan experience high rates of post-traumatic stress disorder (PTSD) and suicidal behavior. Suicidal ideation is among the strongest risk factors for completed suicide. Some research suggests an association between PTSD and suicidal ideation, and that health-promoting behaviors-behaviors that sustain or increase well-being-play a role in this association. The current study examined whether health-promoting behaviors moderate the association between PTSD severity and suicidal ideation. METHODS: Veterans of Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF; N = 108) completed measures of PTSD symptoms, trauma exposure, suicidal ideation, and health-promoting behaviors. RESULTS: Moderated regression was used to test the hypothesis. Results indicated that health promoting behaviors, β = -.06, p = .001, and PTSD symptoms, β = .36, p < .001, were significantly related to suicidal ideation. Consistent with our main hypothesis, the health promoting behaviors x PTSD interaction term was significantly associated with suicidal ideation, β = -.09, p = .001. The overall model accounted for 13% of the variance in suicidal ideation. Among individuals with high PTSD symptom severity, those who engaged in more health promoting behaviors reported less suicidal ideation than those who engaged in fewer health promoting behaviors. CONCLUSIONS: Health-promoting behaviors could be important for reducing suicidal ideation among veterans with high levels of PTSD symptoms. It is recommended that future research examine health promotion interventions as a means of reducing suicidal ideation.