In a nation sample of 75 countries around the world, higher suicide rates of the total male, and female population corresponded to higher levels on the superordinate K factor from differential K theory, thought to reflect a set of mutually interrelated life history and reproductive strategy traits. Countries ranking high on suicide rates concurrently ranked high on national intelligence estimates, longevity, and affluence, whilst low on rates of births, infant mortality, HIV/AIDS, and crimes (rape, serious assault, and homicide). These findings integrate previously reported positive population-level associations between suicide rates and cognitive ability variables into the conceptual space of differential K theory. The propensity toward suicidal behavior is a positive correlate of the K superfactor.