In order to identify differences in risk factors for suicide attempts throughout adolescence, this study utilized a school-based survey of ninth (n = 1,192) and eleventh graders (N = 1,055). Suicide attempts were associated with cigarette and alcohol use, family violence, and depression for ninth graders and with illicit drug use, school violence, and sexual abuse for eleventh graders, while having friends was protective for both groups. Additionally, having more than one risk factor imparted an exponential risk for suicide attempts (ninth greater than eleventh graders). The differences detected are consistent with developmental changes of adolescence and represent important information for identification of at-risk youth.