There is a growing body of research aimed at identifying predictors of suicide risk among Veterans. One predictor may be hostility, as hostility and anger are associated with greater suicidal ideation among Veterans. The interpersonal theory of suicide suggests hostility may be associated with suicide risk through perceived burdensomeness and thwarted belongingness. The aim of the current study was to investigate associations among hostility, perceived burdensomeness, thwarted belongingness, and suicide risk among a sample of Veterans enrolled in a clinical trial. Participants (N = 90) completed self-report measures assessing the variables of interest. When accounting for previously identified risk factors, namely posttraumatic stress disorder, major depressive disorder, alcohol use disorder, traumatic brain injury, and family history of suicide, there was an indirect effect of hostility on suicide risk through perceived burdensomeness, but not thwarted belongingness. Specificity analyses assessing alternative predictors and mediators provided further support for the model. Findings suggest that hostility may require greater clinical attention among Veterans at risk for suicide.