Well-being in the broadest sense is what we have when we are living lives that are not necessarily morally good, but good for us. In philosophy, well-being has been an important topic of inquiry for millennia. In psychology, well-being as a topic has been gathering steam very recently and this research is now at a stage that warrants the attention of philosophers. The most popular theories of well-being in the two fields are similar enough to suggest the possibility of interdisciplinary collaboration. In this essay I provide an overview of three of the main questions that arise from psychologists’ work on well-being, and highlight areas that invite philosophical input. Those questions center on the nature, measurement, and moral significance of well-being. I also argue that the life-satisfaction theory is particularly well suited to meet the various demands on a theory of well-being.