Surveyed two high school cohorts (ns=698 and 283) to study independent prospective predictors of adolescent suicidal behaviors (thoughts, communicatio to others, attempts). Within each cohort, there were two measurements conducted 6 months apart. Structural equation models were tested, with depressive symptoms, hopelessness, alcohol consumption, social support, and gender serving as predictors. In the larger cohort, depression predicted later levels of all three suicidal behaviors controlling for baseline suicidal behaviors. Also, suicidal thoughts predicted later communications, and suicide attempts predicted future thoughts. In the smaller cohort, alcohol consumption predicted all three suicidal behaviors at the later measurement, whereas depression was predictive only of later thoughts. Major issues regarding prevention, theories of suicide and negative affect, and methodological/analytical approaches were discussed.