Students who violate school smoking policies present a difficult health and disciplinary issue for school officials. Professionals know little about the characteristics of students who smoke at school. In a prospective study of 679 students in two cities in central Massachusetts, researchers examined how nicotine dependence contributes to the problem of smoking at school. After three years of follow up, smoking at school was reported by 10.3% of students. Among subjects who admitted to smoking at school, 63% reported that symptoms of nicotine dependence preceded their smoking at school. After adjusting for other variables, student smokers with symptoms of nicotine dependence were nine times more likely to report smoking in school (OR 9.1, 95% CI 2.9-28.5) than were student smokers without symptoms. Smoking at school was more common among daily smokers and those who paid for their own cigarettes. Age, gender, race, and parental smoking status were not significantly associated with students' reports of smoking at school. These data suggest nicotine dependence as an important contributor to the problem of smoking at school, but not the only reason why students violate school smoking policies. Disciplinary action against students caught violating school smoking policies should be supplemented with an offer of treatment for nicotine dependence.