Obesity is not only a health but also an economic phenomenon. This chapter (a) examines underlying economic causes, such as technological advancements, behind the obesity epidemic; (b) describes economic consequences of obesity, including increasing obesity-related medical expenditures; and (c) discusses the role of government in combating the obesity epidemic. Because of the high costs of obesity, and the fact that the majority of these costs are financed by taxpayers, there is a clear motivation for government to try to reduce these costs. However, because obesity may result from poor information and addictive behavior and/or as a result of living in an increasingly obesogenic environment, interventions will need to be multifaceted to ensure the best chance of success.