The objective of this systematic review of observational studies was to gain insight into potential determinants of various types and intensities of physical activity among adult men and women. Studies were retrieved from Medline, PsycInfo, Embase and Social scisearch. The ANGELO framework was used to classify environmental factors. In total, 47 publications were identified. Social support and having a companion for physical activity were found to be convincingly associated with different types of physical activity [(neighbourhood) walking, bicycling, vigorous physical activity/sports, active commuting, leisure-time physical activity in general, sedentary lifestyle, moderately intense physical activity and a combination of moderately intense and vigorous activity]. Availability of physical activity equipment was convincingly associated with vigorous physical activity/sports and connectivity of trails with active commuting. Other possible, but less consistent correlates of physical activity were availability, accessibility and convenience of recreational facilities. No evidence was found for differences between men and women. In conclusion, supportive evidence was found for only very few presumed environmental determinants. However, most studies used cross-sectional designs and non-validated measures of environments and/or behaviour. Therefore, no strong conclusions can be drawn and more research of better quality is clearly needed.