This systematic review investigated the environmental (physical, economic, socio-cultural and political) correlates of active transportation (AT) among young people aged 5-18 years to better inform the promotion of active living. Greater distance, increasing household income and increasing car ownership are consistently associated with lower rates of AT among children. Having a non-white ethnic background has a convincing positive association with AT. Having recreation facilities and walk or bike paths present are possibly associated with higher rates of AT. Further research requires longitudinal and intervention studies, utilizing multi-level design methodologies and objective measures of environmental attributes.