This chapter discusses the association between socioeconomic status (SES) and obesity, with a focus on explanations for the inverse association between SES and obesity in high-income countries. In addition to a review of the most common explanations, including that the relationship is spurious, due to underlying differences in human capital and/or due to SES group differences in the consumption of energy dense foods, we review the hypothesis and evidence thereof that the association is due, in part, to the direct effects of perceived scarcity on weight-related behaviors.