Dispositional optimism is the generalized, relatively stable tendency to expect good outcomes across important life domains. This article provides a representative review of 30 years of research on dispositional optimism and physical well-being. Assessment of optimism is described, along with data regarding its stability. A review of the research linking optimism and physical health is then presented. Included in the review are initial studies suggesting that optimism and physical well-being might be linked as well as more recent, larger scale epidemiological studies that make the point more emphatically. Also considered are potential pathways-behavioral, biological, and social-that might explain these associations. The article concludes with a brief look to the future, describing several issues and questions that still need to be answered. These questions include the relationship of optimism and pessimism to each other (and the implications of that relationship for physical well-being), the origins of optimism and pessimism, and interventions that might be implemented to reduce the negative impact of a pessimistic outlook. (PsycINFO Database Record (c) 2018 APA, all rights reserved).