Active commuting to school (ACS) is a promising strategy to increase physical activity among adolescents. While characteristics of the built environment influence commuting behaviors, they may also shape parents’ perceptions of social norms related to ACS. This study analyses how subjective and objective built environment characteristics, at both micro- and macro-scale, are associated with parents’ perceptions of the social norm. When the built environment was considered as whole in a multivariable model, only the density of sports facilities (a macro-scale measure) was linked to parents’ perception of social norms, while subjective and micro-scale characteristics were not. These findings imply that environments with visible opportunities for physical activity, such as sports facilities, may shape parental perceptions of ACS as normative behavior. The presence and design of such facilities could be considered in planning, with macro-scale variables emerging as the most informative measure capturing associations with the social norm.