This study used linked, official data for population-based surveillance of homicides, suicides, and homicide–suicides in four U.S. states and four counties. Among 1,503 homicide incidents, less than 5% (n = 74) were followed by the perpetrator’s suicide and 1% (n = 18) by a nonfatal suicide attempt. However, among men who killed their female intimate partner with a firearm, 59% also took their own life. Homicide–suicide perpetrators did not test positive for an antidepressant more often than other male suicide decedents (15% vs. 19%). Most (54%) perpetrators of nonfirearm homicides who attempted suicide lived; nearly all (93%) firearm perpetrators who attempted suicide died. Among men who killed their female intimate partner with a firearm, homicide–suicide was the norm. Better enforcement of existing laws designed to protect abuse victims by removing firearms from domestic abusers may also prevent abusers’ suicides.