This is the first study to our knowledge to examine the relationship between happiness and longevity among a nationally representative sample of adults. We use the recently-released General Social Survey-National Death Index dataset and Cox proportional hazards models to reveal that overall happiness is related to longer lives among U.S. adults. Indeed, compared to very happy people, the risk of death over the follow-up period is 6% (95% CI 1.01-1.11) higher among individuals who are pretty happy and 14% (95% CI 1.06-1.22) higher among those who are not happy, net of marital status, socioeconomic status, census division, and religious attendance. This study provides support for happiness as a stand-alone indicator of well-being that should be used more widely in social science and health research.