It was within this context that we designed a randomized trial to test whether high school student participation in advocacy activities related to the advertising ,availability, and use of tobacco in their communities would prevent or reduce their own tobacco use. We conducted the trial in continuation high schools because of the high cigarette smoking rates of their students. We designed a new advocacy curriculum in which students carried out activities to counter environmental-level smoking influences in their schools and communities (advocacy or “treatment” group) and tested it against an existing curriculum in which students learned about drug and alcohol abuse prevention (control group). We hypothesized that students in the treatment high schools would experience a significantly greater decrease in cigarette smoking than students in the control high schools, and that the reduction in smoking would be maintained for 6 months following the intervention. We also hypothesized that students in the treatment vs the control high schools would experience more positive change in 3 social cognitive constructs that may predict successful involvement in advocacy activities.