We examined the association between various dimensions of the family environment, including family intimacy and involvement in activities, family support for physical activity, and neighborhood violence (perceived and objective) and physical activity among urban, predominantly African American, ninth-grade girls in Baltimore, Md. Greater family intimacy (P=.05) and support (P=.01), but not neighborhood violence, was associated with physical activity. Family factors, including family intimacy and support, are potential targets in physical activity interventions for urban high-school girls.