This systematic review—a review of the body of evidence on a subject—identified which environmental interventions increase physical activity for residents while also considering intervention costs. Furthermore, this study examined how the effects of these interventions differ by ethnicity and socioeconomic status. Interventions such as parks and playgrounds and active transportation facilities showed an increase in active transportation, visits to parks, and physical activity. There was some evidence that these kinds of interventions benefit socioeconomically advantaged groups more than other groups.