There remains a great need for effective, cost-efficient, and acceptable youth smoking cessation interventions. Unfortunately, only a few interventions have been demonstrated to increase quit rates among youth smokers, and little is known about how elements of cessation interventions and participants' psychosocial characteristics and smoking histories interact to influence program outcomes. Additionally, few studies have examined how these variables lead to complete smoking abstinence, reduction or acceleration over the course of a structured cessation intervention. Data for the present investigation were drawn from a sample of teen smokers (n=5892) who voluntarily participated in either a controlled study or field study (i.e., no control group) of the American Lung Association's Not On Tobacco (N-O-T) program between 1998 and 2006 in five states. Results suggest that those who reduce smoking (but do not achieve full abstinence) are similar to those who quit on most measures except stage of change. Furthermore, it was found that those who increased smoking were heavier smokers at baseline, more addicted, were more likely to have parents, siblings, and significant others who smoked and reported less confidence in and less motivation for quitting than did those who quit or reduced smoking. Finally, a path model demonstrated how peers, siblings and romantic partners affected tobacco use and cessation outcomes differently for males and females. Implications for interventions are discussed.