Barriers to and facilitators of walking and bicycling to school were explored through 12 focus groups made up of fourth- and fifth-grade students and their parents who lived near their respective schools. The barriers and facilitators reported by parents and children generally fell into one of three categories: intrapersonal and interpersonal characteristics of parents and children, environmental characteristics of the neighborhood, and environmental and policy characteristics of the school. Findings indicate that a supportive environment is a necessary but insufficient condition to increase walking and biking to school. Initiatives to increase active school travel may need to include multiple levels of intervention to be effective. (Contains 4 tables.)