In developed countries, obesity is inversely associated with socioeconomic status (SES) among women, and less consistently among men; whereas, in developing countries, the association is direct. However, the relationship of SES to weight change over time is unknown. This relationship was the focus of the present literature review. It was hypothesized that, compared with persons of higher SES, persons of low SES would show greater weight gain or risk of weight gain over time. A search of electronic databases identified 34 relevant articles from developed countries reporting on studies that assessed the relationship of various measures of SES with weight change over time in adults (there were too few papers from developing countries (n = 1) to include). Results of the methodologically strongest studies (those which obtained objectively measured adiposity data and used a follow-up period of 4 years or more) showed that, among non-black samples, there were relatively consistent inverse associations between occupation and weight gain for men and women. When SES was assessed using education, evidence was slightly less consistent, but still provided some support for the hypothesized relationship. However, when income was used as the indicator of SES, findings were inconsistent, although there were fewer studies available. There was little support for a relationship between SES and weight gain for black samples. In the context of the worldwide epidemic of obesity, these findings suggest that in developed countries, weight gain prevention efforts might best be focused on those who are most socioeconomically disadvantaged, particularly those in lower status occupations.