Suicide rates among U.S. military personnel and veterans are a public health concern, and those with mental health conditions are at particular risk. We examined demographic, military, temporal, and diagnostic associations with suicidality in veterans. We conducted a population-based, retrospective cohort study of all Iraq and Afghanistan war veterans who screened positive for posttraumatic stress disorder (PTSD) and/or depression, received a suicide risk assessment, and endorsed hopelessness about the present or future after their last deployment and between January 1, 2010 and June 29, 2014 (N = 45,741). We used bivariate and multivariate logistic regression analyses to examine variables associated with having endorsed suicidal thoughts and a plan. Multiple factors were associated with suicidality outcomes, including longer time from last deployment to screening (proxy for time to seeking VA care), an alcohol use disorder diagnosis, further distance from VA (rurality), and being active duty during military service. Hispanic veterans were at decreased risk of having suicidal ideation and a plan, compared to their white counterparts. In high-risk veterans, some of the strongest associations with suicidality were with modifiable risk factors, including time to VA care and alcohol use disorder diagnoses. Promising avenues for suicide prevention efforts can include early engagement/intervention strategies with a focus on amelioration of high-risk drinking.