Active commuting (non-motorized transport) to school can be an important source of physical activity for children and adolescents. This research examined sociodemographic, family, and environmental characteristics associated with active commuting to or from school among 3,451 US adolescents aged 12-17 years, who responded to the 2005 California Health Interview Survey. Logistic regression results indicated that those more likely to actively commute were males, Latinos, from lower-income families, attending public school, living in urban areas, and living closer to school. Adolescents without an adult present after school and those whose parents know little about their whereabouts after school were also more likely to actively commute. Parental walking for transportation and perceptions of neighborhood safety were not associated with adolescent active commuting. Important family and individual correlates of walking or biking to school among adolescents were identified, even after adjusting for distance to school and urbanicity.