 This systematic review aims to identify which environmental interventions increase physical activity in residents at the local level, while considering intervention cost and differential effects by ethnicity and socioeconomic status. The study found that walkability components, quality parks and playgrounds, and active transport infrastructure positively affect active transport, physical activity, and visits or use of settings. However, there is some indication that infrastructure improvements may predominantly benefit socioeconomically advantaged groups. Studies were limited by selection bias and insufficient controlling for confounders, leading to heterogeneity in study design and reporting. Further investigation is needed to improve the quality of evidence and determine if the benefits of infrastructure improvements are inequitably distributed. This article was authored by Melody Smith, Jamie Hosking, Alistair Woodward, and others.